Paradise Hotel 51

Where Gaming Dies


Think of incidents in your life that you wished never occurred.
Wouldn’t you wish to erase that past from your memory?
If said past is detested, then killing the past would erase it from existence.

Mr. TD

Kill the Past” is a loosely connected series of videogames revolving around the lives of individuals who are in conflict with their pasts in an ever-changing sociopolitical and technological landscape. It’s the life work of Goichi Suda, also known as SUDA51, CEO of Grasshopper Manufacture. The connections between his earlier games were something of an open secret until 2001, during which Suda confirmed that most the titles he released up until that point formed a continuous narrative. As such, the series has no official title: “Kill the Past” is a tagline used several time within said games, which was adopted by Japanese fans as away to refer to the series itself.

Goichi Suda a.k.a. SUDA51
In this 2001 interview with the website GPara, Suda confirmed that Moonlight Syndrome, The Silver Case and Flower, Sun and Rain are all connected to each other, and he considers them a trilogy. (Source)

What does ‘Kill the Past’ mean?

Kill the Past” refers to one who dwells on a traumatic event from their past; one who only manages to maintain their self-consciousness by repeating a set of patterns that reflects their past. Their trauma must be confronted head on in order to move forward.
In Suda’s own words, you must kill the past in order to fight for the future, which was reflective of his design philosophy.

The phrase ‘Kill the past’ also shows up in your past games. Have you thought about killing your past? Why? Do you hate the past, and if yes, why?
I have seen a lot of people who only remain themselves by repeating the same things they’ve done in the past and I really don’t want to be like them. Killing the past is also synonymous with fighting with the future, and what makes the future alive is facing the past and settling things.
Basically, I don’t want to cling to the same past things when I make games, since the players also want to see something new. I only look at the possibility of making games that face the future.
That means fighting the future.


This core tenant is reflected in all aspects of the KTP mythology; Ghosts are not depicted as wandering spirits, but rather as Remnant Psyches, a lingering thought of the past that won’t let go of the present. In many cases, the push for urbanization is depicted as the original sin responsible for severing the thread of tradition, erasing national culture and catapulting the characters into nightmarish madness. The main conflict in each game tends to revolve around a past incident, often several decades old, that went on to shape the characters’ own reality and worldview.

Who are the protagonists of Kill the Past?

Each game of the series follows a different cast of characters, each with a different perspective in life.  
(Moonlight Syndrome: high-school students; The Silver Case & The 25th Ward: detectives & a reporter; Flower, Sun and Rain: self employed professional; Killer7: political assassin; No More Heroes: pop-culture obsessed otaku; Kurayami Dance: undertaker.)
This diversity in points of view and lifestyles is what allows the series to explore a wide variety of settings and themes (ranging from geopolitics to forbidden love, the superficiality of pop culture or the relationship between violence and political power) while maintaining its core themes throughout. 

The KTP setting is based around the human perception of the world. Just like in real life, nobody has all the answers to life, death and spirituality. 
Therefore, details about the world, the information you are given and even the look and feel of the game, will reflect the state of mind of the player character, and will thus vary wildly from game to game.
Here’s an interesting quote from Suda 51 in relation to Moonlight Syndrome, which I think applies to most other KTP games. 

Could the story of Moonlight Syndrome be considered to have taken place within Ryo’s inner universe? Or do the inexplicable events that occur during the story actually occur in the real world?

What would happen if the phenomenon of mental revolution that Ryo undergoes, triggered by the death of Kyoko, happened not just to him but to the whole of Hinashiro? The headmaster, Kimika Takahashi, the people at the club… If all of the people scattered across town, too many to depict, were to simultaneously undergo this internal revolution…

I think of it as a realistic story with this exaggerated to an extreme.

Ryo definitely does exist within Hinashiro, and he experiences a realistic story up until Dowaku. There is no definite explanation for the epilogue. You could say that all of the characters in the story are walking along by themselves, and so at one point I had to rewrite the epilogue due to the circumstances of their journeys. The events are completely different.


My personal interpretation being that the settings themselves could be considered an externalization of the characters’ inner turmoils. The world as is it presented to the player is being shaped by their individual perspectives, hence why every game has a distinct look and feel.

How do the games connect to each other?

The plot of the Kill the Past series is like a river. Each game fills in more and more details about the overall setting, but no matter what, the story keeps on moving forward without an end. 
Characters will begin their arc in one game, just to finish it in another. Characters can also be killed off screen, or moved on to a completely different walk of life through the years.

The over-arching plot works the same way; It cannot be grasped in its entirety just by playing one game, because each game usually adds a new layer to the plot or concludes a story arc from a previous one.

The first few titles in the series (from the Syndrome games to The 25th Ward) form a continuous narrative, where each game follows up directly from the previous one within the same setting and timeline. Since the release of Killer7, Suda made an effort to transform “Kill the Past” into an anthology series, where each game would be set in its own self-contained world, while still carrying on the themes, motifs and mythology which originated in Moonlight Syndrome. However, since the release of Travis Strikes Again, a concerted effort has been made to retcon these disparate titles into one all-encompassing setting once more.

What is the chronology of Kill the Past?

The chronology of this series can be very confusing, especially considering that most Grasshopper Manufacture games include references or continuity nods to each other.
To make things simpler, I decided to segment the core titles into three broad eras.
This chronology is based on in-game dates, official complementary materials such as guidebooks, fanbooks and the Silver Case timeline on its official website.
More often than not, each game takes place in or close to its release year. 
There is also a variety of ancillary materials that were written by either Suda Goichi himself, or long time collaborator Ooka Masahi, and could be considered canonical.

The Syndrome Era:

The Syndrome games actually predate the foundation of Grasshopper Manufacture. Suda Goichi worked on these games while he was an employee of Human Entertainment. His control over the project grew exponentially; Initially stepping in as a replacement for the director halfway through development of the first game, by the time Moonlight Syndrome came out he had enough influence as the main director and writer to turn the game into a wholly original, esoteric project that is considered controversial among Syndrome fans to this day.

This era also marked the beginning of the collaboration between Suda Goichi and Ooka Masahi, who would later act as co-writer on many of the following games. He was the writer of the Truth Files, collections of faux journalistic reports retelling the story of Moonlight Syndrome.

1996-1997: Twilight Syndrome

Twilight Syndrome actually refers to a duology of games: Tansaku-hen (Search Chapter) and Kyuumei-hen (Investigation Chapter), which had to be split in two releases due to production issues.

The main writer for Twilight was Hiroshi Kasai, with most of the scenarios having been planned before Suda even came in as Director; As such, it’s not overtly indicative of Suda’s own writing style. However, it has to be included as its direct sequel, Moonlight Syndrome, which he wrote and directed, serves as the bedrock of his Kill the Past mythology.

Twilight Syndrome is a horror-themed adventure game revolving around a trio of high-school girls: Yukari Hasegawa (the player character), Chisato Itsushima and Mika Kishii, investigating ghostly apparitions in their hometown of Hinashiro. The upbeat and child-like Mika is usually the one dragging her two upperclassmen with her to investigate various rumors; Yukari, while initially reluctant due to her more serious nature, begins to spend more and more time with Mika in order to avoid her distressing family life, and the spiritually savvy Chisato follows along to make sure the two don’t get into any real trouble. Through the course of the game, their bond develops into an unshakable friendship.

The theme of killing the past is present, but it is mostly related to exorcising the past sins that caused the ghostly apparitions rather than the focus on personal trauma it would take later in Suda’s career.

1997-1999: Moonlight Syndrome

This game is the origin point of most of the recurring themes and motifs of the KTP universe. While the Twilight Syndrome games are chronologically the first games in the timeline, this game can be considered the true start of the canon. 

This game is described by Suda himself as a psychological horror; while, on a surface level, it retains the supernatural horror elements of its predecessors, the focus is put squarely on the characters’ inner turmoil and psychology.

The Moonlight Syndrome after which the game is titled refers to the way moon phases influence human behavior and sanity. Which is why characters tend to behave erratically and crazy through the game, a Lunatic being a person who is particularly influenced by the lunar phases.

The full moon would make a return in all subsequent KTP games in one form or another; The full moon itself also carries a theme of transformation, which may be related to the concept of killing one’s past in order to move on to the future. It is worth noting that repressing one’s memories often has the effect of transforming said character into a completely different person.

The game’s main plot revolves around the relationship between Ryo Kazan and Mika Kishii, a returning character from Twilight Syndrome.

Mika, now in his second year of highschool, bears a striking resemblance to Kyoko Kazan, Ryo’s sister, whom he loved in a way that was abnormal for a pair of siblings.
Kyoko suddenly dies in a motorcycle accident, but her head goes missing. Ryo’s grief is deep, but through a chance encounter he notices how closely Mika resembles his dear Kyoko.
The appearance of a seemingly demonic white haired boy transforms this chance encounter into a tragedy.

This game also pioneered the structure of most KTP games to come, according to which the game is separated into episodes, most of which are stand-alone stories only tangentially related to the main plot, but still revolving around the white haired boy and the Moonlight Syndrome. While the Twilight Syndrome games also had an episodic structure, Moonlight Syndrome was the first one to also have a strong over-arching narrative mixed in with the stand-alone episodes. 

Other canonical media:
Moonlight Syndrome Truth Files
Yocyou and Rinne (short stories)
Inyaku (short story)

More on the Syndrome franchise:

Twilight Syndrome: Reunion

The Twilight Syndrome franchise is actually much bigger than the three games I listed. After Human Entertainment closed down in 1999, Spike (later Spike-Chunsoft, a company founded by ex-Human employees) acquired the brand and produced two more games, Saikai (Reunion) and Kinjirareta Toshi Densetsu (Forbidden Urban Legends), a trilogy of live action movies meant to coincide with the release of the games, a pachinko machine and I would assume several other ancillary materials.

Due to Suda’s departure from Human and general fan reception, everything in the Syndrome franchise following Moonlight Syndrome either ignores or contradicts the events of said game; that is to say that the Kill the Past series and the Twilight Syndrome series, from this point onward, are completely separate.

I am not going to cover any of the Spike-era Twilight Syndrome titles, for the simple reason that Suda had no input whatsoever in their development and as such they would not inform the overall picture of his career.

The Twilight Syndrome also made an appearance as a videogame franchise in Super Danganronpa 2, another Spike-Chunsoft title.

The Silver Era:

This era encompasses the first few games that Goichi Suda wrote and directed after founding his own studio, Grasshopper Manufacture.
The supernatural aspects of the Syndrome games are still present, but they exist in the background as the main plots focus mostly on political intrigue and conspiracies.
It is during that era that the “Kill the Past” tagline made its debut.

1999-2000: The Silver Case

The Silver Case could be considered the main plot of the KTP multiverse, as it is the game that establishes what is canon and what is not. Even Killer7, which is set in a different continuity/timeline, still borrows heavily from The Silver in terms of structure, mythology and themes. 
Plus, while later KTP games seem to revolve around one character, the Silver Case games follow a variety of characters belonging to a multitude of organizations. TSC could be described as a collection of stories that develop and evolve the setting and themes that were originally portrayed in Moonlight Syndrome. 

In The Silver, we indirectly learn that the story of Moonlight was actually an isolated incident that was in effect part of a larger overarching story, as its very first episode serves as the resolution of Moonlight’s cliffhanger ending.
In a sense, Suda actually killed the past in order to move forward with an entirely different set of characters, while at the same time expanding upon the same setting and core ideas that began in Moonlight. (The full moon shows up before every single chapter, as the political intrigue of the Silver Case grows more and more insane.)

The bulk of The Silver Case takes place within the fictional 24th Ward of Tokyo, within the independent nation of Kanto.
The legendary killer Kamui Uehara awakens after 20 years of being institutionalized as a vegetable, and goes on a killing spree. 

In the Transmitter arc, the player is put in the role of a new recruit in the Heinous Crime Unit, which deals with Transmittable Crimes, and is set to investigate the resurrection of Kamui Uehara, unraveling the secrets behind the foundation of the 24th ward in the process. 
(The player character is actually a blank slate through which the player experiences the events of the game. For all intents and proposes, he’s not really the protagonist of the Transmitter arc. Tetsugoro Kusabi, a hard-boiled, veteran cop, and Sumio Kodai, his rookie apprentice, could be considered the real protagonists of Transmitter.)

In the Placebo arc, penned by Masahi Ooka and running concurrently with the Transmitter arc, the player witnesses the case from the eyes of reporter Tokio Morishima, enriching the lore of the 24th Ward and explaining background details of each case from the point of view of a civilian.

Other canonical media:
Prequel Comic “PreLunatics”
Case 4.5: FACE

History of the 24th Ward

2001: Flower, Sun and Rain

This game is a sidequel to The Silver Case, in the sense that it is not a full blown sequel, but it follows up on certain story threads from The Silver while featuring some returning characters in a different setting. 

The game revolves around a “searcher”, Sumio Mondo, who is hired by the management of the Hotel “Flower, Sun and Rain”, located in Lospass resort, to find and stop a terrorist who has planted a bomb on an airplane. 
However, when checking into his room, Sumio is alerted by the manager, Edo Macallister, that the island is trapped into a groundhog day style time loop: The same day keeps repeating over and over, and the same plane keeps blowing up at the end of each day. 
The core conflict is determining who the terrorists are, and how to defuse the airplane bombs in time. 
Of course the plot isn’t as simple as it sounds. What exactly is Lospass resort? Why does time refuse to move forward? Most of all, who is Sumio? 
The game ties up several loose ends from The Silver Case, while at the same time opening up an entirely new set of questions which will be expanded upon in the following title. 

2005: The 25th Ward

A direct follow up to The Silver & F.S.R., this game was originally released episodically on Japanese cellphones between 2005 and 2007. It received a widespread release on consoles and personal computers in 2018. 

Set in the eponymous 25th Ward of Tokyo, the game explores a new, experimental society in which people are encouraged to compete with one another over meaningless status symbols, while the Regional Adjustment Bureau, under the cover of the Postal System, will “adjust” (i.e. execute) citizens for any kind of minor violation. 

In the Correctness arc, the player once again takes command of a nameless police officer which may or may not be the same as the original Silver Case, while following the exploits of the 25th Ward Heinous Crimes Unit. Namely, detectives Shiroyabu (a naive momma’s boy) and Kuroyanagi (a hard-boiled cop, a sort of female Tetsugoro Kusabi), while they investigate the Regional Adjustment Bureau.

Meanwhile, the Matchmaker arc follows Tsuki and Osato, two agents of the Regional Adjustment Bureau, as they go through their “adjustment” routine while confronting an enemy from Tsuki’s past. 

The Placebo arc once again follows Tokio Morishima, now an amnesiac, who has been hired to investigate the secrets behind the 25th Ward while trying to recover his own past. 

It should be pointed out that the tagline for this game is actually “Kill the Life” rather than “Kill the Past“, even though the concept of erasing one’s past is still a relevant theme within the game. 
“Kill the Life” actually refers to the shadow of Uehara Kamui, threatening to awaken once again to destroy “the life” (i.e., the “everyday life” or lifestyle of the 25th Ward). 

At this point in time, this is the end of the original TSC story arc. Suda has jokingly referred to his plan for a 26th Ward game (Source), but what might come of that remains to be seen.

Other canonical media:
Red, Blue and Green

Alternate Timeline: Killer7

Killer7, being the first GhM game to be developed specifically to be released in the west, does not actually take place within the main Kill the Past timeline. Suda’s own stated reasoning was that by making the game self contained, he would be able to communicate the core themes and ideas of The Silver to an international audience, who would not have been familiar with his previous work.

Killer7 takes place in a world where the internet and all transcontinental flights are banned, in order to decisively eradicate the threat of terrorism. The Superpowers’ nuclear arsenals are disarmed, and world peace is achieved.
However, a new breed of religious terrorism, the “Heaven Smile”, starts targeting governmental institutions. The only group that can combat the Heaven Smile threat is the assassin syndicate, the Killer7. 
The player takes the role of the eponymous Killer7 as they are employed by the government to hunt down Heaven Smiles and their leader, Kun-Lan. What the public is unaware of, though, is that the Killer7 are actually comprised of one person, being able to physically transform into his different personalities. Harman Smith, the legendary assassin. 

While the premise and presentation are completely different than earlier games, Killer7 borrows heavily from The Kill the Past mythos.
The mission structure mirrors that of The Silver Case. 
The prologue is a self-contained incident serving as an introduction to the main characters and setting. 
The first mission introduces the main plot.
The second mission is an unrelated case.
The third mission focuses on the backstory of one character of the main cast.
The fourth mission is about propaganda, and how information is spread.
The fifth mission is when everything goes to shit, most of the main cast is killed off and the truth is revealed about a decades old incident. 
The sixth mission is an epilogue where the consequences of the final chapter are explored.

Killer7 actually had an equivalent to the Placebo reports planned during development, but it was ultimately scrapped. It is however included in the official handbook as the Jaco Reports. 

Killer7 also has a multitude of cameos from past KTP games, though as stated in the Hand in Killer7 interview, those should be viewed as just that, cameos. Killer7 cannot coexist within the same timeline as The Silver due to the conflicting backstories detailed earlier.

 – Is there a connection between Killer7 and your previous games?

There are cameo appearances. However, there are copyright issues involved, so I created them so that if you asked me if there were a direct connection between the games, I’d say “no.” In my head, I’m creating them in one big world, but the individual settings of the stories are completely different, so it’s not like these stories can be told in the same timeline.

That being said, the story still revolves around a character who has erased his own past, and now lives through the consequences of having done so. Plus, concepts such as Remnant Psyches, the TV being used as a spiritual medium and using a paper bag to carry a human head are lifted straight from past KTP games. 

Other canonical media:
Killer is Dead (short story)
Hand in Killer7

The No More Heroes era:

Through this era of Suda’s career, the supernatural and political aspects of the setting are mostly set aside, though they still exist in the background; a larger focus is instead given to satirical comedy and pop culture references, both aspects that were present in his previous titles but have now taken center stage.

Continuity is not as strict anymore; the world of No More Heroes does not follow tridimensional logic, the fourth wall is broken constantly and then broken again to acknowledge its metanarrative.
(It should be noted that fourth wall breaks were also present in previous Suda games, but never had a central role in the narrative itself before the NMH era.)
As such, the games tend to cover more absurd territory; Giant robots, kaijus, aliens, superheroes, tiger gods and talking animals are but a sample of what you’ll come across in the No More Heroes era games.

2007: No More Heroes

No More Heroes was originally conceived as a stand-alone game, unrelated to previous Suda titles (Source), following up from Killer7 in an effort to transform Kill the Past in an anthology series. However one of its sequels, Travis Strikes Again, re-contextualized the game as a part of the original KTP timeline. That is to say, it now takes place two years after The 25th Ward.

In the nondescript american town of Santa Destroy, Travis Touchdown lives the superficial life of a pop-culture obsessed otaku: collecting figurines, watching anime and wrestling matches, playing with videogames and with his cat Jeanne. His day-to-day life is disrupted once the mysterious Sylvia Christel, during a drunk night at the bar, contracts him to assassinate a “drifter” in exchange for a hefty sum of money.

As soon as the assignment is carried out, Sylvia shows up once again to inform him that by killing the drifter Helter Skelter, Travis officially joined the ranking system of the UAA (United Assassin Association), thus making himself a target for any assassin that is ranked below him. Travis has two choices: either run for the rest of his life, or aim for the top spot in the UAA rankings, killing everyone who stands in his way. 

No More Heroes was somewhat of a minor hit with general audiences, ushering in a new era for GhM in which they mostly focused on violent action games featuring a snarky sense of humor. Games such as Shadows of the Damned or Lollipop Chainsaw.

Other canonical media:
Past killing to future killing
The Outer Rim

2010: No More Heroes 2: Desperate Struggle

Three years after Travis settled the score with his past, Santa Destroy is taken over by industry giant Pizza Bat (formerly Pizza Butt) with the help of mobsters; a retired Travis is forced back into action when his best friend Bishop, owner of the video store, is gunned down during the takeover.
He is once again forced to climb the ranks of the UAA in order to take down the CEO of Pizza Bat, who just so happens to be the Number 1 Ranked Assassin.

This game was not directed by Suda Goichi, and as such it is lacking the original No More Heroes satirical edge. Its storyline is played completely straight, both in comedy and in drama. I personally do not find this game to be interesting or appealing enough to analyze for a variety of reasons, but it is included here since, due to TSA, it has been cemented as part of the timeline.

Other canonical media:
No More Losers
No More Heroes 1.5

2014-2017(?): Kurayami Dance

NOTE: This is a manga, which was written by Goichi Suda and was based on one of the original scenario drafts for “Shadows of the Damned”. While it was only released in Japan, it has since been translated by Twitter user Falions.

Wataru is an undertaker by day, and a biker by night. One day he decides to test his limits by surpassing 300 MPH on his bike. He claims to be doing so not out of a desire to die, but rather, because he’s in a hurry to live.

This results in a near fatal accident. Wataru wakes up in a mangled body, which takes three years to be fully restored.
Once he awakens, Wataru finds his hometown changed to the point of being unrecognizable: most of its inhabitants moved to “the castle”, a newly developed urban area which seems to operate under different laws than Japanese soil.

As soon as he returns to his workplace, he is immediately offered a job that would lead him to that same castle that everyone seemingly moved on to.
Wataru eagerly accepts the job, feeling that confronting the castle is the only way to reclaim the three years he lost. Everything in The Castle seems to have a connection to his past; what is this world that Wataru awakened into, and what is the abstract presence that keeps following Wataru wherever he goes?

I decided to include this as a main entry because, despite the medium of choice, the story has a similar structure to Flower Sun and Rain, Killer7, or No More Heroes, in the sense that it follows the protagonist’s quest to confront his past and come to terms with it, interacting with a setting that seems to be an externalization of his own repressed memories.
While Killer7 was heavily political and No More Heroes had a satirical element related to how geeks/gamers perceive the world, Kurayami Dance is a more personal story which revolves around coming to terms with childhood memories and experiences.

It should be noted that the timeline placement is just my personal assumption based on certain connections that this story shares with Travis Strikes Again.

2017: Travis Strikes Again

Seven years after the events of No More Heroes 2, Travis Touchdown has abandoned friends and family to live in isolation in his trailer house, collecting gaming memorabilia. Shigeki Birkin aka Badman, the father of one of Travis’ victims, finally manages to track him down in order to enact revenge on him. However, just as they are fighting, they get sucked in by the Death Drive Mark II console, which is said to be able to make a wish come true if its six games are found, and completed. Travis and Badman then decide to team up in order to have Badman’s daughter be restored to life.

This game happened to be Goichi Suda’s return to the director’s chair after ten years, since the original No More Heroes game, and he took the chance to tie in the NMH games to the original KTP timeline, while providing closure for a few outstanding plot points along the way. Namely, one of the side characters of the game is actually from The 25th Ward, and the ward itself is visited during the course of the game.

Due to its nature as an anniversary title (TSA marked the company’s 20th anniversary), most other GhM games are referenced in one way or another; Suda himself started referring as his shared universe as the “Sudaverse” or “Grasshopperverse” around this time, an interconnected multiverse where characters from disparate worlds and settings can meet and co-exist, explaining how characters from Killer7 are able to appear right next to Travis, or Kamui Uehara.

2021: No More Heroes III

Four years after the events of Travis Strikes Again, Travis once again returns to Santa Destroy, only to find himself in the middle of an alien invasion. FU and his cronies, allied with EA’s President urban developer Damon Riccitiello, have taken over Santa Destroy and turned it into a futuristic “utopia”, painting themselves as Superheroes in the process.

Travis, alongside Shinobu and the newly resurrected Bad Girl, returns to the world of dead end jobs and senseless murder in order to join the Galactic Superhero Rankings and save the world from space aliens and corporate meddling.

Unfortunately, due to strict timetables and presumably other budgetary concerns, most of the connections that this game was going to establish with the larger catalog of Suda’s games were left on the cutting room floor. (Source.) It does however retain some overlap, namely with The 25th Ward, Travis Strikes Again and Red, Blue and Green.

Suda has expressed interest in continuing the No More Heroes series in the form of spin-offs, sequels or even live action adaptations. However, as of 2021, most of the IP rights have reverted back to Marvelous, making GHM unable to operate without their consent. (Source 1, Source 2.)

Several news outlets rushed to claim that Suda himself had supposedly announced the “end” of the No More Heroes franchise (here’s an example) but to my knowledge, that is merely a misunderstanding of Suda’s tweet, in which he is referencing both the Galaxy Express 999 movies, and Evangelion 3.0+1.0. He has been quite vocal about eventually retiring Travis Touchdown as a playable character, only to turn him into a mentor figure for the next No More Heroes protagonists, which if anything, is an indication of his willingness to continue the series rather than to end it.

Miscellaneous References

There is also a number of other Grasshopper Manufacture games that contain references to KTP games.
Though it must be noted that they lack a strong narrative connection to those titles and their storylines do not necessarily carry on the Kill the Past mythos or themes. As such, I listed them as separate games.
Due to the concept of a Grasshopperverse being introduced in 2017, different timelines and realities can now cross over and interact; that is to say, the events of these games did not necessarily take place in the same world as The Silver Case.

1992: Super Fire Pro Wrestling Special: Champion Road
– The Wrestler Thunder Ryu would make an appearance in No More Heroes, as Travis’ master.
– Morio Sumisu, the protagonist of the game, is alluded to in No More Heroes. 

2004(?): Michigan
– The Balboa Brothers from Flower, Sun and Rain are mentioned in a note.
– The Ishizaka conglomerate that appears in most GhM games is referenced in the form of Zaka TV.

2006(?): Blood+ One Night Kiss
– Ishizaka corporation is once again referenced.
– The two cops, Aoyama and Akama, share the same names as the ones in The 25th Ward.

2011: Shadows of the Damned
– It exists as a videogame franchise within the main canon, as shown in Travis Strikes Again.

2012(?): Diabolical Pitch
– Santa Destroy and Lospass are referenced within the game.
– Its protagonist, the legendary pitcher MacAlister, has a brief appearance in Travis Strikes Again.

2012(?): Lollipop Chainsaw
– The main character has a very short cameo in Killer is Dead.

2013(?): Killer is Dead
– The main character has a short cameo in Travis Strikes Again.

2020(?): Super Fire Pro Wrestling World: Champion Road Beyond
– Direct sequel to Champion Road.
– The co-star, Notorious, also appears in Travis Strikes Again and No More Heroes III.

2026+: Let it Die
– The Death Drive console is used to play through the game itself; a different model of the same console would make an appearance in Travis Strikes Again.
– The construction of the 26th Ward is alluded to in one of its areas, as it is in some endings of The 25th Ward.
– The Earth Rage earthquake is mentioned both in this game and in Travis Strikes Again.
– Mejin, one of the supporting characters, seems to be styling himself after Master Taro Gida, a legendary gamer alluded to in Travis Strikes Again.

Simplified Chronology

Here’s a simplified chronology for quick reference. Main games are in red, side-games (which may or may not be canon) are not.

1992: Super Fire Pro Wrestling Special: Champion Road

1996-1997: Twilight Syndrome: Tansaku-hen / Kyuumei-hen
– Twilght Syndrome: The Truth Files

1997-1999: Moonlight Syndrome
– Moonlight Syndrome: The Truth Files
– Yocyou
– Rinne
– Inyaku

1999-2000: The Silver Case
– Prequel Comic
– The Silver Case 4.5: Face

2001: Flower, Sun and Rain
– Lospass Guidebook
– One Island, One Resort, and One More Episode

2004(?): Michigan

2005: The 25th Ward
– Red, Blue and Green

2006(?): Blood+ One Night Kiss

2007: No More Heroes
– Past killing to future killing
– The Outer Rim

2010: No More Heroes 2
– No More Heroes 1.5
– No More Losers

Alt. History 2010-2014: Killer7
– Hand in Killer7

2011: Shadows of the Damned (is released as a videogame)
– Kurayami Magazine

2012(?): Diabolical Pitch

2012(?): Lollipop Chainsaw
– Prequel Manga

2013(?): Killer is Dead

2014-2017(?): Kurayami Dance

2017: Travis Strikes Again
– Killer is Dead (short story)

2020(?): Super Fire Pro Wrestling World: Champion Road Beyond

2021: No More Heroes 3

2026+: Let it Die