Gradius IV – Gradius Portable Guidebook Interview

Ashida Hiroyuki: Zako enemies, design, and overall direction.
His main works include Gaiapolis, Detana Twinbee, and Gradius II.

Yoro Daisuke: Enemy and background design. Also helped
out on bosses. He is known for Bishibashi Champion and others.

Stage 1 – Liquid Metal

Ashida: For Gradius IV, we didn’t think about the order of the stages while we were designing them. So when it came time to choose the most suitable stage for stage 1, we went for something with a lot of visual impact, and that was the Liquid Metal stage.

Yoro: Also, I think Gradius IV was the first in the series to use polygons. We were searching for something to show off those new possibilities when we came up with this stage.

Ashida: The emphasis on visual impact made it resemble Gradius II, and I think it turned out to be a bit of fanservice to Gradius fans. By the way, when we decided to make the liquid metal planetoids have a reflective surface, it turned out we couldn’t use the effect on very large or irregular polygons. So we ended up with the small, very round planets. As for the stage 1 boss, he’s the type that changes his shape during battle. We decided in the beginning to make 3 separate transformations, but we argued about what they should be until the very end. (laughs)

Yoro: Yeah, we had ideas like a turtle, a seahorse, some spinning thing…

Ashida: Also, we deliberately made the strength of the boss change depending on what he transformed into. I think the green one was the easy one. I seem to remember the white turtle was strong.

Yoro: I think that idea came from me having a pet turtle. (laughs)

Stage 2 – Plant

Ashida: This was one of the first stages we made.

Yoro: That’s right. Our theme for Gradius IV was “interactive.” So the tendrils move in a unique way and react when the player shoots them.

Ashida: They snap back at you, if you shoot them too much.

Yoro: Yeah. We wanted players to be able to interact with the game in that way, where they’d be uncertain what would happen as a result of their actions. The plants are one instance of that idea. Only when the player is shooting does he interact with elements in the game world, so we had a discussion about how we could visually present this “interactive” motif, and the plants came out of it. We also argued a lot about the spore mist that appears in the latter half of the stage. At first we made it so thick that you couldn’t really tell where bullets were coming from.


Concept art for the plant stage.

Ashida: For this boss, we tried to make his attacks unpredictable, but it turned out that they have a pattern that can be memorized. (laughs)

Yoro: We messed up the game balance with his arm that extends out and attacks the player. Its instant death if you’ve never seen it before. It was really too powerful.

Ashida: We created that boss according to the “Gradius theory” of boss design: each boss has a combination of a weakspot, something that defends that weakspot, and something to attack with.

Stage 3 – Bubble

Ashida: This stage is difficult because there’s an element of luck involved. Gradius had been known as a pattern game, but changing it from a pattern-based game to one that relied more on player’s reflexes was one of our fundamental design ideas for Gradius IV. That choice is reflected very strongly in this level, and because of that, I think its a particularly hard level for longtime fans of Gradius who were used to memorizing patterns.

Yoro: Yeah, the fact that you’d need to execute a slightly different strategy each time you played was an intentional move on our part.

Ashida: In addition, I wanted to create something that looked soft and fluid. In Gradius III there is also a bubble stage, and though the bubbles look soft and “bubbly,” there’s also a mechanical aspect to them that looks unrealistic. Using polygons, I wanted them to break apart more finely and realistically. I especially wanted to show how a bubble shrinks and contracts when a smaller part breaks off.

Stage 4 – Magma

Ashida: I remember saying “We have to include a Volcano stage!” (laughs) But we wanted the tone to be more realistic, and for the rocks to have a rugged, craggy feel. We also changed the color of the stage to distinguish it from the Plant stage.

Yoro: Yeah, and the magma doesn’t come till the second half of the stage. I remember we kept revising the way the lava looks and acts up to the very end. Making the terrain move with the waves of lava gave us a lot of trouble.

Ashida: Another example is the enemy sets… we couldn’t get them to work right. Even after we placed the Duckers and other enemies on rock platforms, the lava moved too much for them to be very effective. Even with placing the flying zako enemies, the constantly twisting terrain undermined our efforts to arrange them in the way we wanted. For the really violent movements in the latter half, we actually created that part according to a pattern. We first figured out how the player ship should navigate the section, and then afterwards we added the terrain movement and enemies.

Yoro: We strived to make it feel like you were battling with the terrain.

Ashida: And of course, having the boss be a dragon who enters in the middle of the screen is one of those promised Gradius conventions we had to honor. (laughs) Since the eyes were his weakpoint, we decided to encase the head in that armor.

Yoro: We worked hard on this design so the weak point can be clearly distinguished. Same for the turtle.

Stage 5: Moai

Yoro: There was a lot of disagreement about the Moais.

Ashida: The way the Moais work in the Gradius series is already firmly established, so I think all the arguing was kind of pointless.

Yoro: As a tradition in the game, they were pretty much worn out by then. We felt like we were beating a dead horse.

Ashida: In Gradius II, we made the Moai stand up and spin around, and in Gradius III we made them really large. So we asked ourselves what we could do for Gradius IV, and the idea of infinitely respawning Moai is what we came up with.

Yoro: That was something we tried towards the end, just to see how it would look. But it turned out to be really fun so we used it for the vertical Moai as well.

Ashida: Yeah, it felt like it would be too easy to clear with only horizontal Moai, so we decided to add vertical ones too.

Yoro: With a fully powered ship it was just too easy to get through it. To make it harder we made the ion rings from the revived Moai force the player to move further and further forward, making it increasingly hard to dodge. We did that because by this time, there were too many expert STG players. We had to make it so they could enjoy the the game too!


Moai henchmen.

Ashida: For the boss, we were pretty much left to our own devices. They told us as long as there’s a big Moai and small Moai, we could do whatever we wanted.

Yoro: We wanted a new weapon for the Moai boss, something really difficult and strong, and we came up with the little “Moai henchmen” you see. We were able to do whatever we wanted with the boss, like the lasers coming out of the little Moai’s eyes. (laughs)

Stage 6 – Cell

Ashida: This was the last stage we made.

Yoro: That’s right. Our image for the stage was “blood vessels.”

Ashida: The Gradius series always has breakable walls. Most players who have made it this far will be fully powered-up, so we designed it to be very difficult if you just thoughtlessly destroyed everything. Instead, you’re supposed to veryyy carefully advance without spraying bullets everywhere. (laughs) We also made the weakpoint harder to shoot for the rampaging tentacle enemies that appear later in the stage.

Yoro: We had been wanting to make something grotesque for Gradius IV. (laughs) I wanted it to be a little eerie and disturbing, too. The way this stage reacts violently to you when you attack it was also part of the interactive design we were going for. As for the boss of this stage… well, that was our attempt to make a Golem style boss. (laughs)

Ashida: I remember this boss being relatively easy to design and explain to the staff. I designed it so you could get inside the space between the small tentacles near the eye, but that it wasn’t a “safe spot”… I worked hard to get rid of the safe spots on this boss. When he dies he fires off a bunch of lasers, but there’s a pattern to it and its dodgeable.


Early concept art for an unknown stage.

Stage 7 – High Speed

Ashida: The high speed, boss rush, and fortress stages all appear at the end of the game here in quick succession. For the boss of stage 7, I wanted to add some kind of shield to his front and rear, but it wasn’t working right because of the way he moved. We deliberately wanted to make a boss who could rotate so naturally and easily, unlike previous core bosses in the series.

Stage 8: Boss Rush

Yoro: The zub rush was very popular with the staff at Konami. (laughs) So we definitely wanted to add that.

Ashida: We had never shown a boss coming out of a space cruiser the way you see in the Gradius poster, so we wanted to show that in-game here (and in the attract mode, too). Also, when we decided we would add a boss rush to Gradius IV, we thought we’d feature a series of original new bosses rather than rehashing previous ones. I especially wanted to make Vanishing Core’s searchlights, the way it shoots at you if you’re caught in them. (laughs) We really enjoyed making Big Core MK III Kai, too. We made his movement very smooth, and he can change the angle of his reflecting laser. We gave Covered Tetran normal bullets and mine attacks. Mixing bullet types like that is a common feature of Gradius bosses. For Berserk Core, we didn’t expect players to find that safe spot. The idea with Planet Core was to make him a stronger version of Covered Core.

Yoro: Planet Core was the most difficult for us…

Ashida: I feel like our design ideas came from it being round.

Yoro: I remember saying it was big, so we’d make it like a planet…

Ashida: Ah, that’s right. And the little guys he spits out were supposed to be moons or satellites. (laughs) And there you have Planet Core.

Stage 9: Base

Ashida: The base stage is another Gradius mainstay, but I think flipping the orientation vertically in the middle of the stage was a first.

Yoro: At first the programmers told us it couldn’t be done, but we just made them do it anyway. (laughs)

Ashida: We knew we wanted to do that pretty early on, but it took a long time and actually ended up being late.

Yoro: Gradius is always a horizontal scrolling shooter, so they were like, why in the world are we making this vertical…

Ashida: Well, we did want to surprise everyone. (laughs)

Yoro: I remember making it rotate smoothly was a challenge.

Ashida: With the midboss Bloody Gate, we intentionally left the safe spots in. Safe spots are a part of the Gradius series, after all. There are things in Gradius we wanted to change, and things we wanted to keep the same.

Yoro: We probably made him red because we wanted him to look intimidating. (laughs)

Ashida: And those spinning weights that come after that midboss were definitely part of our “interactive” theme. Doesn’t the Crab boss appear after that?

Yoro: We were really worried about his movements looking too comical. I remember we also were stressed out about the last boss.

Ashida: We were. (laughs) If he’s going to be an organic being, how do we portray him? I remember we tried to make him embedded in a test tube at first. In the end we made a model that showed his face, though.

Yoro: Yeah, he would have looked really weak if we put him in a test tube. (laughs) His face looks a lot different than Gofer from Gradius II.

Ashida: And yet, his name is Gofer. (laughs)

The meaning behind the “Fukkatsu” subtitle 1

Yoro: In arcades it was the era of fighting games, though there were less and less of those games as well. Music games were starting to dominate everything, and in the midst of that we wanted to signify the “revival!” for shooting games.

Ashida: Games in general were all starting to be polygon based. And for Konami too, they had released very few traditional 2D arcade games by then. But the title also conveys the meaning that Konami still was dedicated to arcade games, and we wanted to make that clear with the title “fukkatsu.”

Yoro: It really has a lot of different meanings. There was the revival of Gofer, the revival of arcade games generally… and there was also meant the revival of the stoic STG, in contrast to danmaku games, which were the majority of STGs at the time.

The Gradius IV concept

Ashida: Other than the interactive quality that we’ve mentioned already, visually speaking we had wanted to make a 3D Gradius game. But the truth is, that idea would have really fettered the traditional Gradius gameplay because Gradius is about navigating your ship through 2D spaces and bullet patterns. We also considered using the 3D to show enemies approaching from far away, but we wanted to keep the gameplay itself simple, so we abandoned that idea. We ended up deciding to keep the gameplay 2D, but add depth to the visuals with 3D. When bullets are in 3D, it just becomes too difficult to determine hitboxes. So we ended up really diluting the 3D aspect we had originally envisioned, and even the terrain ended up being relatively flat so as to allow the player to better judge collision detection.

Six Different Ships

Ashida: In Gradius III there was an edit mode, but that made the game difficult to balance. We decided to avoid that from the beginning and thought of various workarounds, but we had a hard time coming up with new weapons. Gradius II was a fairly balanced game in this regard, so we decided to expand on that game and add two more equipment types and put the new weapons there. Those were the vertical mine and the flying torpedo.

Yoro: For armor piercing, I designed that by starting with an idea of what the weapon’s hitbox would look like. Then I extrapolated outwards from there as to what kind of weapon would fit that hitbox, and created visuals for it.

Ashida: One thing we worked at was making sure each weapon setup had advantages and disadvantages. We often hear that vertical mine is very strong, but armor piercing is very weak, and that was done intentionally.

Length of Development, Size of Team

Yoro: Our staff was changing a lot at the time, so I can’t say exactly how many were working on it.

Ashida: There was a period in the middle where the project was put on hold. More than half the staff was changed when it resumed. So the length of the project really depends on where you draw that line… for our group, I think we took around 10 months?

Yoro: I think that’s about right. It was a bit longer for me.

Ashida: I actually was invited to join as Director later in the project. They were like, “Hey, you know Gradius, right?” (laughs)

Your Personal Favorite

Yoro: Gradius II for me.

Ashida: I worked on Gradius II. I was a new hire at the time, and they told me: “We may be making Gradius II, so why don’t you just get started on it now?” (laughs) They handed me Salamander and Gradius as references and I remember playing those for about 2 months. On Gradius II I drew the stage backgrounds. And so Gradius IV probably has a lot of influence from Gradius II. There were a lot of staff members that loved Gradius II also, and we would have discussions about whether we should make such and such like Gradius II, or whether we should do something different.

The Redesigned Vic Viper


Lego version of Gradius IV ship, by pasukaru76.

Yoro: I think the Vic Viper was revised more times than the stages. I forget how many months we spent on it, but I do remember people saying they didn’t like it. (laughs)

Ashida: Its slimmer than the previous incarnations. We asked ourselves, what was the real charm of the Vic Viper? It has a sort of grey-ish color in-game. In the original Gradius, its design was sharp, in Gradius II it gets sharper, and in Gradius III it looks smart and stylish. Since we were redesigning the Vic Viper in 3D polygons, we decided to emphasize that sharp appearance. My original image for the Vic Viper in-game was a little more round… the tail area should look a little more weathered and rough. But our design really highlighted its sense of speed, I think.

Allowing Continues

Ashida: The overseas version of Gradius II had allowed continues, but none of the domestically released Gradius games did. We decided to add them this time, and I remember saying “Even if you continue in Gradius, you still have to perform a checkpoint recovery!” (laughs)

Yoro: There are players who really enjoy checkpoint recovery. Everytime I go to a location test and see the players I’m impressed by how good they are. (laughs) So we wanted to make a game that would be fun for them, too. On the other hand, that doesn’t mean you can just abandon new users, and for that reason we added continues to Gradius IV. The game center operator could decide whether to turn continues on or off, so it was only an option.


Yoro: The second loop playtesting was limited to players who were already very good.

Ashida: We checked the first loop to make sure recovery was possible from every checkpoint. In the second loop and after, there are slight changes in the terrain and background, so we checked those very closely. We also decided during playtesting to use the “Parodius” rank system: dying once lowers the rank, and dying twice lowers it further. We wanted to give players a chance before Game Over.

Checkpoint Recovery

Ashida: Since we made Gradius IV, its often been said that the Gradius series is a kind of puzzle game. That puzzle flavor was especially strong in Gradius III, and I think for a certain kind of Gradius fan, its one of their favorite features.

Yoro: Yeah. For fans who didn’t like our system, I don’t think it was so bad that they completely abandoned the game, but our concept for Gradius IV was that it would be interactive. If you moved like this, the enemies would respond like this, and we designed it so each time it would be a different experience. Of course, a lot of it can still be reduced to patterns and memorization. (laughs)

The second loop of Gradius IV,
featured in STG Weekly #1.

Later Loops

Ashida: For the second loop and beyond, the instructions we got from staff was pretty much “do whatever you like.” (laughs) So we had a meeting with the team about loops, and the question came up: just because its a Gradius game, do we have to keep doing these loops? But it was decided that having them would make certain players happy, so we ended up adding a really challenging second loop.

Boss Names

Ashida: I named all the bosses, but I don’t remember who named all the other enemies. I basically said to whoever created an enemy, “name him what you like.”

Yoro: Alpha and Omega [[Aa and Muu in Japanese]] were named after the person who made them, Ayumu. He might get mad if he sees this. (laughs)

Ashida: Yorogaton Kimera was named by Yoro and another developer. Everyone said it was an awful name. (laughs)

Stage ideas that didn’t make it

Yoro: In the end we didn’t do it, but weren’t we planning to make a water stage?

Ashida: Now that you mention it, I remember that too.

Yoro: When we brought up the idea of a water stage, someone asked “how should we do it?” and the response was “yeah, what should we do…” And the idea pretty much died on the table there. (laughs) There was an idea to do a stage with a lot of waterfalls, I remember.

Ashida: I remember someone asking “what happens to the Vic Viper when its in the water?”

Yoro: Yeah, someone asked that. But we thought it would be weird if the ship died by touching the water, so we’d have to make it a background feature only… and if that was the case, we said we might as well abandon the idea. I think some of those ideas were used in the bubble or magma level, though. Let’s see, what else was there…?

Ashida: I don’t know if I really want to reveal this, but… there were talks of adding a puzzle game feature where you’d shoot a globe or ball, and you’d have to make it roll by shooting it.

Yoro: Another idea we had was a “fake” Vic Viper that would appear and fight you one-on-one. We thought “this will be awesome!”, but when we actually tried it, it was really boring. (laughs) I know this idea was suggested for Gradius III too, and when they tried it, the enemy ship was too hard to hit and it wasn’t very fun. Later, I remember discussing what we should do about the Moai, and there was a very busy day when we had to sleep over at Konami. I was sleeping, when suddenly Ayumu came up to me and said, “Yoro, I’ve got it! Bagworm Moai!” (laughs) I said “what the hell is that?” and he said “I don’t know”… and we went back to sleep. I think he must have been dreaming of a meeting or something.

Ashida: He must have meant the Moai should be hanging or suspended from something.

Yoro: Probably… but it would have been dumb anyway, I think. (laughs)


A concept draft of the puzzle stage idea mentioned above by Ashida.

Memories of Gradius IV

Yoro: For me, this was my first important project. It was the first project I’d participated in from the very beginning. So in that sense it was a difficult experience, truly.

Ashida: I don’t really remember the day-to-day details. We were just too busy. One reason my memory is blank is that we would usually write all our ideas on a whiteboard, and everyone would use that as a reference while they worked. (laughs) So now that its been erased, I don’t remember much.

Yoro: There had been many Gradius games before this, so there was a lot of pressure on us to create a worthy “IV.” I have mixed feelings about it: I feel a sense of pride and superiority in some of the things we accomplished, and with others I wish we could have done something different.

Ashida: Since I joined as director halfway into the project, there were employees who looked at me in a negative way: “what are you doing here?” (laughs) That was really difficult. I think everyone has their own sense of what Gradius should be, and how a Gradius game should be made.

If you were to make a new Gradius…

Yoro: I think the possibilities would be overwhelming. (laughs) What to do, how to make it new… I really enjoy bringing my ideas to life, but I think with the arcade format its especially difficult. Maybe if it was a console Gradius. But yeah, I could get lost in it…

Ashida: I’d like to make a new Gradius–as long as no one complains or cares if its a commercial failure. (laughs)

Yoro: There’s no way that will happen. (laughs)

Ashida: I know, but if someone gave me that level of freedom to really radically reconstruct Gradius, I think I’d like to try it. When you’re told its ok to break the rules, that’s when new things happen; but if you’re told to make something new AND honor all the old traditions, its extremely difficult. If I made another Gradius, I’d want to break some of those rules.