
Twinkle Star Sprites x Rival Megagun interview
In this 2018 interview originally featured at 4gamer, Twinkle Star Sprites creator Yoshiyasu “Casio” Matsushita and Rival Megagun creator Justin Rempel came together to discuss the creation of their respective games, their mutual respect and the trials and tribulations of working in the somewhat niche subgenre of head-to-head STG.
Yoshiyasu Matsushita – creator & designer of Twinkle Star Sprites
Justin Rempel – creator & programmer of Rival Megagun
—Let’s start with Matsushita. Please tell us how you came up with Twinkle Star Sprites’ unique “versus shooting” systems.
Matsushita: Soon after joining ADK, I decided to enter an in-house game design competition. At the time, ADK was making fighting games like World Heroes, but because fighting games were expensive and time-consuming projects, the company held a competition in order to devise a small project that could be produced very quickly. I wanted to be a game designer, so I submitted the proposal that formed the basis for Twinkle Star Sprites.
—In the midst of the fighting game boom, the company wanted something with an immediate turnaround, and that’s where you came up with the idea of “versus shooting”.
Matsushita: The company suggested I make something with a head-to-head focus, so I took their suggestion and combined it with what I was into, which was shooting games.
—When one thinks of “versus shooting” they might imagine something like Chameleon Army / Space War, where the players shoot at each other directly, but Twinkle Star Sprites has a very unique system: the screen is divided into dedicated play fields for P1 and P2, and by exploding enemies to create chains of destroyed enemy waves, you can can attack your opponent by launching popcorn enemies into their play field. Where did these ideas come from?
Matsushita: Right before the deadline for that design competition, my boss warned me upfront that he didn’t think a game where the players shot directly at each other would do very well, to which I reflexively replied “well, I’ve been thinking about dividing the screen vertically and having players compete that way…”. That caught his interest, so I was tasked with writing a proposal based on that concept, but the reality was I hadn’t given any thought whatsoever about a game with a vertically-divided screen. (laughs)

—He told you a direct shoot-out style of game was off the table, and by narrowing down your options, you were forced to come up with something new.
Matsushita: A head-to-head shooting game where both players share the same play field would certainly be easy to make, but making something fun would be much harder.
—Back then, when the fighting game boom was at its peak, there were a lot of head-to-head games with players sharing the same play field, but the format brought its own complications when applied to shooting games.
Matsushita: You can probably put that down to the difference in character control between fighting games and shooting games: in a fighting game, the characters are human, so it’s easy to understand attacks like punches and kicks and intuit how certain moves might lead to openings in one’s defense, but with a shooting game, the nature of the characters’ actions, even just shooting a bullet, aren’t always going to be immediately obvious. For that reason, I think, my boss wanted me to come up with something different.
—I see, so you needed to take a different approach.
Matsushita: Yes. In order to meet the conditions of creating “a versus shooter that didn’t use a shared play field”, I had to come up with a system that would meet the contradictory aims of allowing players to attack each other while segregated to either half of the screen.
—Direct conflict across separate play fields… that must have been quite a challenge.
Matsushita: I knew indirect attacks would lead to the game becoming more puzzle-like, but I wanted to make a game where those who who were good at shooting games would be strongest. With that goal in mind, I came up with a system where chained explosions would send popcorn enemies over to the opponent’s play field which could then be reversed by the recipient—the players weren’t directly shooting at each other but their shooting game skills were being tested, and this system allowed for really intense matches.
—Intercepting popcorn enemies definitely requires a certain level of fundamental shooting game competency, so I think that intent was reflected in the final game. What difficulties did you face when designing that system?
Matsushita: Because the type of game we were making was more or less uncharted, there was nothing we tried that wasn’t difficult. As development progressed, every new idea was open to scrutiny, and it seemed impossible to come up with something that’d please everybody.
—Because you were coming at the genre from a new angle, you had to re-examine a lot of established conventions, from the game system to the play feel.
Matsushita: As I was struggling to figure things out, all sorts of requests were coming from the people around me: “the character’s movement should be locked to the horizontal axis”, “maybe the play field should become smaller and smaller and eventually kill the player”, and many other out-there ideas.
However, that type of fixed side-to-side movement seemed like a relic from the ’70s and it was frustrating to die to something due to the restricted movement. If players aren’t freely able to duke it out, we might as well kill the project… those were my thoughts at that point. I did actually try out those ideas, but none of them were the least bit appropriate for a “versus shooter”.
—You were simply looking to add a versus element without discarding the freedom and feel of a ’90s shooting game.
Matsushita: Therefore, we came up the idea of using explosions from defeated enemies to cause chains that would launch enemies at the opponent and eventually summon bosses once certain conditions were met; by devising an original game system that’d let players interfere with their opponent’s play field, we were able to make something in the form of a modern vertical shooting game but with a competitive edge.
—Was it tough to devise such a system with so little time?
Matsushita: Settling on solutions was difficult, but sleuthing them out was fun. The programmer was very skilled and was able to realize my ideas with a high degree of accuracy.
—So you had more than just ideas, you also had the people to see them through.
Matsushita: The biggest roadblock was the concept of “dodging AI”—I wanted the CPU to move like a real human being, without simply, programmatically dodging every attack.
—It’d definitely suck if the opponent in a versus game like this one could mechanically dodge everything with superhuman reflexes.
Matsushita: Getting it to work was quite tough, but the programmer pulled it off for me. I was very impressed by the finished product, and when I saw it I was convinced the game was good to go.
It was because of his work on the CPU that I split the director’s credit with him on the staff roll. That said, once the game was out, nobody seemed to pay much notice to our “dodging AI”. (laughs)
—Even so, I’m sure the naturalistic behavior of the CPU helped to keep people playing. Twinkle Star Sprites sounds like it was a small project, but how many people worked on it all up?
Matsushita: There were four main team members, and we were able to get additional people to jump in and assist us for two-week stints, so we were fortunate to have a lot of talented people around to pitch in. Artists from the World Heroes and Ninja Master’s teams lent their talents to the graphics, and Takao Oshima, Keiichiro Sagawa and the rest of the sound team provided the fantastic music. I’m still thankful to everyone at ADK who was willing to help out on such a modest project.
—With the help of so many skilled colleagues, you were able to sculpt these unprecedented concepts into something that went over really well with players. Rempel-san, what are your memories of playing Twinkle Star Sprites?
Rempel: I imported the Dreamcast version and my friends and I would get together on weekends to play. The regular game’s fun as it is, but when someone triggers fever and all of a sudden there are loads more enemies being generated by each chain explosion, it suddenly becomes 100 times more exciting. It’s a total rush.
—As the game goes on, the players’ attack power will grow and their screens become chaotic, and dodging anything becomes really difficult.
Rempel: Eventually, I began referring to games with similar elements as “fever games” and started looking for games that were similar. It was like, “Gimme more fever games! What else ya got?!” (laughs)
—Did you find any more “fever games”?
Rempel: Not really. (laughs) The closest was probably Bomberman—when all the players have max firepower and the walls start closing in due to time running out, it starts to feel a little like Twinkle Star Sprites.
—I see… perhaps that craving for more fever games is what pushed you to make Rival Megagun. Why’d you decide to make Rival Megagun, and why’d you decide to make a “versus shooting” game?
Rempel: I’ve loved versus games and shooting games since I was a kid, so when I decided to make a game, a versus shooter was the natural choice.
Matsushita: Ah, versus and shooting… we like all the same stuff. (laughs)
Rempel: Actually, I did try making a few other games but I lost motivation halfway through, but when it comes to versus shooting games, they’re even more fun to make than they are to play.

—Matsushita, what were your impressions after playing Rival Megagun?
Matsushita: I thought it was fantastic. In the wake of Twinkle Star Sprites, there have been many derivative games that took note of the game’s versus puzzle-esque nature and adopted many of the same traits, but versus puzzle games don’t necessarily require you to be constantly engaged—more specifically, the game can essentially stop for one player while they’re setting off their chain.
—Right.
Matsushita: Conversely, Twinkle Star Sprites has no such downtime—even as the players attack each other, they’re constantly on the move. So, in that respect, simply grafting versus puzzle elements onto a head-to-head shooting game as-is has tended not to work very well.
The impression I get from Rival Megagun is that the developers were acutely conscious of these pitfalls and, with that in mind, designed the game to make sure the players were always active. Those big, showy sequences when someone transforms into a boss and invades their opponent’s play field are also really cool.
Rempel: Thank you very much! Arigato gozaimasu!
Matsushita: This isn’t the first head-to-head shooter to let players transform into bosses, but Rival Megagun lets you get right to it, so the tempo’s better. The basic format might be rooted in Twinkle Star Sprites, but the final game is something very different. I’ve never played a versus shooting game like this before.
Rempel: Earlier, you mentioned working to emphasize Twinkle Star Sprites’ head-to-head elements, but I had the opposite approach: I worked to make Rival Megagun feel like an authentic shooting game (that also functions as a competitive game). On top of that, I worked to recreate the feeling you’d get from fever in Twinkle Star Sprites, without simply imitating what you did.
Matsushita: I definitely picked up on all that when I played the game. Whenever a new genre is established, new rivals emerge and the spirit of friendly competition pushes everyone to go all out, so I’m so happy a game like Rival Megagun has come along. It’s got me wanting to make something new, too.
Rempel: By all means, feel free to rip off Rival Megagun. (laughs) Personally, I’d love to see more versus shooting games being released.
An example of Rival Megagun’s flashy boss transitions.
—Rempel, what was the hardest part of making Rival Megagun?
Rempel: Online multiplayer, definitely.
Matsushita: Ah, that’s definitely not easy. I know your pain.
Rempel: When two players are locked to their own play fields, you can fudge things a little, but when one player becomes a boss and enters their opponent’s play field, things have to really stay synchronized, and I was barely able to pull it off.
Matsushita: Maybe you should have written the lore so that all the boss machines were out for repairs or something. (laughs) Jokes aside, in a versus puzzle game, even if the sync isn’t perfect, you can calibrate timings based off each player’s attack. But when both players are shooting at each other in one play field, every attack has to remain in perfect sync, and I’m sure that was really difficult to maintain.
Rempel: That’s right. Regarding the bosses themselves, as I’m sure you can imagine, I struggled not only to determine their attack patterns but also with just making them fun to use at a fundamental level: a big, slow boss that shoots tons of bullets can be fun to fight against but not much fun to control, and on the flip-side, if you make a boss too agile, their attacks become impossible to dodge. Striking that balance was very difficult.
Matsushita: I’m all too familiar with that struggle. Now that I’ve gone hands-on with the game, it feels like you found the right middle-ground.
Rempel: Thank you! Another concern was the amount of bullets on screen—I’m into danmaku, so there was a point where attacks would spew out tons of bullets, but if you go overboard then the recipient is forced to focus on dodging rather than attacking, and if they get attacked in the midst of an intense bullet pattern then they’re no longer able to avoid being hit. Ultimately, I’m happy with the balance we struck in the end, with patterns that don’t get too crazy.
—By the way, are there any shooting games that you both hold in high regard?
Matsushita: I’m not sure I’d strictly call it a shooting game, but Gain Ground. I thought that blend of shooting with the tactical approach of a strategy game was really cool. Gain Ground was a source of motivation back when I was making Twinkle Star Sprites—whenever I was struggling to combine different genres and coming up blank, I’d think, “Gain Ground was able to combine shooting and strategy, so if they could make that work, you can too!”
—There’s a commonality between the two inasmuch as they combine game systems that, at a glance, shouldn’t work well together.
Matsushita: Personally, I often came away disappointed by other genre-hybrid shooting games. Take Fuzzical Fighter, for example: the game touted the ability to have the player ship move on its own via AI, but not only would it not dodge attacks but it’d run directly into enemies… amidst such games, Gain Ground integrated those strategic elements in a very thoughtful and interesting manner.
Another game I really respect is Star Force—Xevious is the shooting game from this era that people tend to talk up, but Star Force was a high-tempo game that went with the idea that all enemies, be they ground- or air-based, could be taken out with a single shot type, and it’s amazing that the template they set back then is still being followed by all current-day shooting games.
—I was big into Star Force. Back then, everyone was crazy about mashing the shot button.1
Matsushita: My other big influence is Cotton. That was a game where characters were pushed to the forefront. The little “manzai demos” in between stages were the drawcard, and the shooting was gravy. Before that point, the world and setting of shooting games tended to be an afterthought, but Cotton flipped the script and showed that it was okay put the focus on, say, cute girls, so when you take into account everything it offered—the shooting, the cute characters, the plot—I consider it a really important game.
Besides those, there are many other shooting games I look up to, including Darius Gaiden and Fantasy Zone, but we’ll be here forever if I start going into detail, so I’ll leave it at that. (laughs) Darius Gaiden in particular is a work of genius, and when I was making Twinkle Star Sprites, that was the yardstick.

—Rempel, which shooting games do you admire?
Rempel: My number one is ChoRenSha 68k. It has a lot of fans in North America, too. Aside from having fantastic music, the layout of each stage in terms of enemy patterns and the different combinations of enemies thrown at you is really well done.
Matsushita: ChoRenSha! It’s great, isn’t it?
Rempel: Of course, I also have to mention RayForce—it’s gorgeous, and the lock-on laser system is unique. I also really like Armed Police Batrider and Sin & Punishment, and there are loads more shooting games I could mention. (laughs)
—You’re both STG maniacs, as it turns out. (laughs) Would you like to make more shooting games in the future?
Matsushita: Of course. I can’t share any details right now, but I have a little something in the works. (laughs)
—I’m sure the fans will be glad to hear it! I’m looking forward to it.
Rempel: I’d love to make another shooting game, for sure, but right now I want to explore other genres. During the making of Rival Megagun, I came up with a lot of ideas about applying a similar head-to-head approach to different kinds of game systems.
—That’d be great, too.
Rempel: In my opinion, the recipe for a good shooting game is: up-tempo music, tight stage design, thirty-second stages, dynamic and over-the-top bosses and the thrill of blowing stuff up. I want to make games in other genres using that same recipe.
Matsushita: I feel you on that.
Rempel: Personally, I like games you can clear in around thirty minutes.
Matsushita: I like games I can play over and over, and games with compact stages, so I really hope Rempel makes an action game! I’m into action games starring buff dudes who swing axes, so something like The Legendary Axe would be cool. Half-naked berserkers, ya gotta make it happen!
In recent years, overseas developers have produced some great shooting and action-platformer games. They really understand the feel of classic Japanese games, so when I look at them from the perspective of a Japanese developer, I know I have to work hard to keep from being outdone.
—Rempel, is there anything you’d like to see from Matsushita?
Rempel: I want you to make another versus shooting game! Twinkle Star Sprites is a game I appreciate for its originality, so if you were to make another versus shooting game, I’d like for it to be something bold and new and not just an iteration on what came before.
Matsushita: Personally, I feel I have a lot left to accomplish even with Twinkle Star Sprites. Working on new games may inspire new ideas, so I’ll give it my best shot.
—Finally, any last words?
Matsushita: I’ll continue giving my all into making games. I’m currently working on several games across various genres, so when I’m able to share more info, I’ll let you know.
Rempel: I love Japanese games, so I hope you’re all able to enjoy Rival Megagun as much as I enjoyed the Japanese games that influenced me. Meeting Matsushita-san was like a dream come true.


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Star Force was one of the first games to heavily incentivize rapid fire, and Hudson’s promotional efforts for the Famicom port hinged around their hypeman and “meijin” Takahashi’s ability to mash the shot button 16 times in one second.↩