BioGun is an upcoming metroidvania that sets itself apart from the rest of the genre thanks to its fine-tuned twin-stick shooter gameplay and the clever ways the developers have leveraged its unique setting as a cartoonish yet thoughtful exploration of dog biology. Rather than swamps and forests, players will be exploring livers, bladders, and other organs where the environmental challenges and game mechanics are often derived from the biological functions of each location.
In an interview with Game Rant, BioGun developers John Rogeles and Ivan Elizalde went into detail about many of their approaches to metroidvania design and the unique challenges that the indie game’s theme and gameplay presented. They also weighed in on the importance of meaningful choices, respecting players’ time, and allowing players to make the game harder or easier through other means besides menu options. The interview has been edited for brevity and clarity.
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Q: The game’s theme brings to mind films like Osmosis Jones and Saturday morning cartoons. What inspired you to make a game that takes place inside of a dog?
Rogeles: When I started working on BioGun it was in 2016 and it wasn’t a metroidvania yet. I was trying to teach myself how to make games with the current engine that we’re using called Construct, and I made a survival shooter just because it’s a great stepping stone toward learning how to program in an engine since that genre is typically a little simpler to make games in. After I made the arcade version–which is still playable to this day–I came back to it a few years later and my wife said, “Hey, you should pick it back up.” And so I did.
The premise was always the same: you played as an antidote or a vaccine, and you’re fighting viruses and bacteria. I realized once I got interconnectivity working between rooms that I wanted to make this a metroidvania. I picked it back up in 2019, and then I began working towards making it a metroidvania.
In February of 2020, COVID was kind of the talk around February. Around that time me and Ivan, one of my best friends of the last 10 years, were talking throughout this process. He hadn’t begun working with me just yet, but, I’ve always shared stuff with him, and he’s always given me feedback at that time. And I told him, “My gosh, this whole COVID situation is crazy. I’m worried that our game’s gonna get politicized because it was about being injected into a human and saving humanity from a viral pandemic.”
Elizalde: Not only that, but at the time it would look like we were just trying to exploit a tragedy. It all just felt a little bit in bad taste.
Rogeles: Absolutely. We didn’t want the focus to be on current events. We wanted people to enjoy the game itself and not be distracted by “Oh, hey, are they pro-vaccine or anti-vaccine?” because people swing different ways. We just really wanted to avoid any of that. So I looked over at my dog while chatting with Ivan and I said, “Wait a minute. How about we change it from humans to dogs?” Which was the catalyst for how a lot of the game’s visual design came about. That gave us a basis for how the NPCs would look and inspired a lot of the themes.
Even the unique option to name the dog that you’re rescuing. Normally, you can name the protagonist in a game, so it was interesting that you could name the dog you’re saving. Flipping that feature on its head was a fun idea.
Q: How has the game’s setting inside of a dog’s body opened up some design opportunities that you might not have had if it were a more typical fantasy setting?
Elizalde: I think being inside an animal opens up a lot more avenues. All we had to do was look at biology to find inspiration. For example, in the bladder, we decided on the mechanic of raising and lowering of fluids based on the fact that the bladder is usually filled with pee.
We’re translating all of these mechanics and locations usually found in other games like swamps and forests, but those other locations don’t give you a lot to be inspired by, right? Whereas the body gives us so much to consider. We started thinking of electromagnetic pulses in the brain, we started thinking about how cells or bacteria travel throughout the body. They travel through the veins, so that led us to make a train station that runs through the arterial system. It feels like a cohesive reason for getting around the body rather than just, “You appear here, and you teleport there.”
I just don’t want to talk too much about it right now, because I feel like we will be giving away the surprise as far as mechanics, but trust that we were inspired mechanically by being inside the body in so many cool and creative ways. I’m really looking forward to seeing players experience our vision.
Rogeles: What’s also kind of fun is what typically may just be a mechanic that you would experience in other games, when you experience them in our game, there is that thematic backing to it. Ivan had brought up raising and lowering the urine levels in the bladder, and now that actually has a thematic backing to it besides just being a mechanic in the game.
I’ll also mention this: the liquid in the liver is poisonous because of the Dooper Virus preventing the liver fun doing its normal functions. It’s fun that not only will you get to experience a game in a unique setting, but you may come to learn some things about biology that you might have never known otherwise.
Q: Were there any challenges in designing BioGun that you feel were unique because of its biological setting?
Rogeles: Absolutely! [Laughs] The art, the direction, there is no visual context at all. You type in on Google, “What does the inside of a liver or bladder or heart look like at a microscopic level?” and you just get a million circles. So you have to translate what you experience in life, what you see outside, and try to make it look familiar yet foreign. There is a balance, because if you make something look too alien, it’s hard to connect with, but if you make it similar and add alien elements, it makes it feel grounded. So that has definitely been the hardest challenge for us.
Q: What do you feel are the core design principles behind BioGun? Were there specific goals regarding how it should feel, how it should play, or mechanics that needed to be present?
Elizalde: Our very first priority when making the game was to make it control smoothly. We decided from the beginning that if we can’t make a game that feels good to play, we’re not gonna make a game at all.
Other than that, we also wanted to have the player be able to play with as many of the mechanics as possible. That way we could incorporate those mechanics into the level design rather than going the traditional metroidvania route where you start out with few abilities and slowly start building up your arsenal. Often in metroidvanias, when you’re fully equipped and ready to have fun, that is where the game decides to end.
I think that people will immediately notice that they have a dash right out of the gate, and then we very quickly give them a secondary weapon. We do have abilities that unlock closer to the end of the game, but the most important parts of the arsenal are all unlocked before the midpoint. Our hope is that players can have a more in-depth experience as early as possible.
Another core principle of the game is what I like to refer to as “meaningful choices.” It’s a phrase that you most often hear in CRPGs and dialogue-heavy games. In our case, we wanted it to be applied to gameplay. There are a lot of moments where you don’t have a distinctive right or wrong decision, and you simply have to figure out what works for you or whatever works at the moment, but you have to give something up. We want players to always be engaged, thinking, and trying to consider what is convenient for them.
A quick small example as to how we apply this philosophy is in the way you upgrade your health or energy. Collecting 3 atoms in the game will net you a Molecule. Molecules are how you upgrade your health and energy, but you have to choose one or the other. Energy will give you more firepower, whereas health will help you last longer in the fight, but it’s up to the player to decide what is most important to them.
Rogeles: Another design principle I’d like to add is that early on in the game’s development, Ivan and I came up with what we call the “five-minute rule,” which is that every five minutes we give something to the player. We felt that it facilitated a great amount of engagement so that players don’t feel like they’re wasting their time. We’ve got a lot of good feedback on that saying that our game’s pacing is a lot of fun and, ultimately, it makes for a better experience even for people that don’t traditionally play metroidvania.
I have a couple of buddies that only play first-person shooters, and thankfully, because we support mouse and keyboard as well–which not many Metroidvanias tend to do–they were able to jump right in and get engaged pretty early on.
As Ivan said, we tried to make sure that the players were empowered pretty quickly. A benefit of this is that starting a new file is a lot smoother. You’ve got the dash, and you can just zip right to where you want to go. That entry barrier is no longer there.
You’ll notice that we don’t necessarily stop the player, besides I think two points in the demo. Otherwise, you can walk as dialogue is happening, or you can skip all the dialogue. We just want to make sure that anybody can jump right in and play. If they aren’t big into the story, that’s totally fine. We know that not everybody likes stories or reading the character dialogue and stuff, but we made sure that the game is designed in a way that whether you love or don’t like those aspects, you can still play from start to finish without getting lost.
Q: Metroidvanias often have some sort of amulet or charm system where players select a combination of powerups, while BioGun’s chip upgrade system focuses on choosing a single meaningful one. What led you to take this approach? Was it to tie into your “meaningful decisions” pillar?
Elizalde: You got it! That’s the goal: having a single more powerful choice. Anytime that you get a chip, it has to always feel meaningful. From the get-go, John and I wanted to make our system stand out from the traditional Hollow Knight or level-up tree system where you get slight upgrades, but you don’t always feel it.
We wanted to have a system where if you install a chip, you immediately feel empowered and notice a gameplay difference. All the chips grant a powerful benefit, but returning to the idea of meaningful choice, the player can only choose one. From the get-go, we want players to start thinking about their preferred method of gameplay.
Rogeles: Every chip is meant to be visceral so you can feel it right away, such as the transistor which allows you to dash and run while healing. With games that borrow the healing system from Hollow Knight as we do, that is a huge change that can almost break the game to some extent. You’ll notice our game is pretty aggressive, so it works in our game. Our main character is pretty powerful. Although the dash may not have iframes, the fact that you can trigger it so quickly makes the character pretty overpowered early on.
We think having visceral chips was the right way to go in a sea of games that give the player many choices, and we felt that it would be a little bit more meaningful to have fewer choices of chips, while instead offering an extremely powerful chip that ultimately changes the game for you in meaningful ways. That’s what we hope people take away from it.
Q: Metroidvania tends to be a challenging genre. What was your approach to the game’s difficulty level as well as its accessibility?
Rogeles: We’re doing our best to make sure that every boss has some sort of tell before their attack happens, which is generally good game design. However, we are aware that our game may not be for everybody. Speaking for myself, I want to avoid making a game too broad because then it loses its flavor. It may be punishing at times or difficult, but as long as it’s fair and the player walks away thinking, “Okay, I lost that fight but I see why I lost that fight” rather than “Because the boss is cheap.”
We do a lot of playtesting of our bosses with friends who are typically gamers, so there’s a lot that goes into them. We also have systems that should help regarding accessibility for players that may not be as skilled, such as the chips being very powerful. In the demo that you experienced, I’m sure you saw the viral protocol chip, which is this little drone that can fly around with you and deal damage and it’s a pretty aggressive drone.
There are also tablets in the game that you can find in chests and they are one-time consumables, but they’re pretty powerful. Sometimes they’re as simple as “this tablet gives you a health point,” so instead of healing you can just quickly eat a tablet and get a health point back. Then there are other tablets, such as one called Metabolic which doubles the speed of your dash so you can trigger your dash even faster. So now you’re really zipping across the floor insanely fast. We’ve got a lot of different ways to hopefully mitigate the accessibility issue, while still keeping the core of the game the way we wanted it.
Elizalde: We absolutely do want as many people as possible to enjoy the game, but we’re cautious of making a game too easy to enjoy the challenge. We do have quite a few systems to help struggling players. For instance, there is a chip later on that can revive you in the middle of a fight. We have seen that chip help so many players. We also have a chip that gives you a shield and tablets that give you back health.
We believe that there are ways for players to make the game easier for themselves if they’re looking for it, it’s just not as simple as clicking an option on a menu and finding the easy mode. The goal is to have the players engage with the systems and be rewarded with an easier game if that’s what they want.
Engaging with the systems can also make the game more challenging if that’s what you want. John and I, for instance, never pick Health as the upgrade when gaining a molecule. We have gone through the game so many times that we hardly struggle with any of the challenges, so having all the energy empowers us to ram through enemies like a wrecking ball.
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It sounds like a more soulslike approach to difficulty where players can make the game harder or easier organically by making decisions during gameplay.
Elizalde: Yeah, it’s a bit like that. However, in contrast to Dark Souls, we do add a little dash of accessibility. We have respeccing options way earlier in case you don’t like your current build as far as health and damage. Or, for instance, we don’t make you run back to the boss fight. We made certain that we had checkpoints very close to the boss fights at all points. Even if you die, you get to keep everything you collected so you don’t need to run back and get it. At all times, we really want players to keep moving forward. We don’t want to hold them back by anything other than their skill.
Rogeles: We didn’t want to force them down a direction. That was an issue that we found with the corpse run mechanic: if you died and dropped items, it forced the player to funnel back into an area they may have not wanted to go back to because maybe they weren’t ready. I don’t see that mechanic benefiting BioGun. Specifically for our game, it would add unnecessary bloat time for the player and periods of frustration.
However, what we do have is something that flips that on its head. Instead, there’s an enzyme that the player drops when they die, which I assume most players will see and assume it’s some kind of corpse-run mechanic, but it’s not. Instead, it’s very beneficial for areas that are tough. The enzyme that the player drops gives you infinite energy for around four seconds, and that will either allow you to immediately start healing yourself within that short period of time or just wail on enemies with your secondary weapons.
Right off the bat, it’s incredibly fun. For boss fights specifically, especially if you’re struggling, that’s technically another accessibility option for some players. They get that little boost of either attack power or being able to heal, or they can strategize by not touching the enzyme yet and waiting until they’re at a critical point with their health, or maybe they need more energy. How the player utilizes this is another choice, as mentioned before.
Q: Metroidvania games tend to focus on melee combat, Castlevania-style, while BioGun plays almost like a twin-stick shooter. How did this combat style affect your approach to enemy and level design?
Elizalde: You probably noticed how short your gun’s range is initially. That’s because we noticed that the game was too easy when the bullets could reach enemies across the other side of the screen and players were being too passive. That’s one of the very early problems that we ran into.
Rogeles: Players may not recognize it immediately, but by having longer range, that essentially forces them to just one type of play style which is “stay far away from the boss” which creates an unengaging gameplay experience. We settled early on for a decent medium range, though definitely longer than your typical melee reach in any kind of melee-based game.
We’ve seen many, many people play and upload their videos on YouTube and typically their first comment is, “Man, I can’t wait to get something with longer range.” This usually makes Ivan and I smile, because although there are options–don’t get us wrong–the mods are balanced among each other including ones that give you longer range.
You’ll notice in the mods menu six different stats are shown and we play with those stats to keep things balanced. How much energy the player gets back, the velocity of the bullet, the life span of the bullet, how hard it hits, and the fire rate. So if it’s long-range, we adjust these stats to balance things out. For example, there is a mod in the game called the Burster mod, which gives the player a comfortable range, however, it shoots in bursts instead and deals just a little less damage than your primary, and it gives you a little less energy.
So ironically, you could say that we didn’t exactly go for an all-out charm system, but by having all these options; chips, mods, tablets, and more, we provide ways players can min-max if they want. The option is there, but we think with the way it’s presented, it’s not as intense of a min-maxing session as other games. It’s not overly cumbersome. You’re not looking at values and numbers. For the most part, you can select a chip or a mod and feel what it does right away, and think, “You know what? There’s that one chip that may actually work out with this mod pretty well.” But nothing too drastic where you’re spending 15 minutes trying to figure out a combination.
Q: What’s your approach to the game’s sense of humor?
Rogeles: It’s definitely meant to be humorous. I could say a big part of that is to separate ourselves from the potential of being politicized. It’s kind of weird because, on one hand, we’re talking about a dog apocalypse, which is really sad. On the other hand, we’re making slight little gags here to make it a little more lighthearted for that Saturday morning cartoon feel that you mentioned earlier.
But also, one of my best friends helps with writing and he and I love Banjo Kazooie. That slapstick humor is definitely woven into the dialogue of the game.
Q: Were there games outside of the metroidvania sphere that you looked to for inspiration?
Rogeles: Ivan and I both foundationally agree on several games that we’re inspired by, which has made it easy to work on ideas together. One of them is Doom with its moment-to-moment gameplay being as engaging as possible. In a later part of the game, just shortly after the demo experience, there is a new mechanic that gets introduced, which I don’t mind divulging here. It is a mechanic that rewards players for using their secondary weapons. We felt like this was a fun next step, but it’s totally optional. Using your energy to power up your secondary weapon and vice versa.
How it functions is whenever you kill an enemy with your secondary weapon, you get this secondary type of energy that increases the fire rate of your primary weapon, so your damage output potential gets increased. We now reward you for using your secondary weapon. It’s like how in Doom when you have an enemy really weakened, and you finish them off and they drop health and ammo.
In our case, if you finish off an enemy with your secondary, they drop a faster fire rate type of energy that you can activate at any time. I can see some players using it if they want, but they don’t have to. It’s totally optional, but it’s there for you, and it can make the combat system pretty engaging and fun against the typical enemies that are strewn about in the game.
Elizalde: There are several other inspirations like Dark Souls and MegaMan. One of the big ones was Breath of the Wild. When we mentioned trying to start with as much of a complete power set as possible early on, It’s because we were inspired by Breath of the Wild and how it turned the Zelda formula on its head. Instead of the typical way of getting a new item per dungeon, Breath of the Wild gave the players almost all of its arsenal in the great plateau, allowing players to play with all the tools throughout the majority of the game.
We do hold back some of the abilities, mostly for the purpose of tutorialization. We don’t want to be like “Here are all the moves and here’s how to use them!” That’s probably gonna confuse a lot of players. Plus, it’s a metroidvania, so you expect your progress and exploration to be rewarded with power-ups. It was really interesting to find the balance between the Breath of the Wild style of giving you everything at the beginning and the traditional Metroidvania style. I feel pretty confident that we achieved a pretty good balance.
Rogeles: Ultimately our approach was to give the core mechanics and abilities early, and then later on give secondary mechanics that are still very fun and stack on top of the core mechanics. That way, the power-ups that you get throughout the game still feel meaningful, but early on they have the tools that they need to explore and enjoy the game and its combat system.
I know that Hollow Knight technically takes this approach too, because they give you wall jumping within two to four hours depending on the player, and the wall jumping just opens up that game like crazy. On the flip side, if you don’t know where the other abilities are, then it can still take a while to get the remaining core abilities of that game. I’ve seen this comment, and I do agree with it: while Hollow Knight gives you a really good ability to traverse the world early on, it takes a while before you can engage with the combat systems at their maximum potential. We prefer having the reverse of that.
Q: Now that the demo has been out for some time, has there been any feedback from players that has struck you?
Elizalde: We can do a little better job of optimizing the game, and we’re working towards that goal right now. Currently, the feedback has been very positive. We hear comments from people preferring or wishing for a different controller layout specifically for gamepad. As John said, we sadly can’t please every single person in the world, but we’re doing our best to be as accommodating as possible by allowing them to rebind their controllers. We’re also adding alternate methods of control.
Rogeles: There’s a preset in the menu, for example, called “manual fire.” If you turn that on, instead of firing your gun when you tilt the right stick, it aims your gun and adds a button to fire.
Of course, you can still rebind so you can adjust it however you need. However, what ends up happening is as you hold down the fire button you can let go of the right-stick, and the aim locks in the angle that you last pressed. This allows you to let go of the right stick to jump while keeping your aim. We personally believe that the Bumper Jumper control scheme is the way to play BioGun.
Although left bumper jumping isn’t the most comfortable, left bumper jumping gives you the most control over the character, whereas the manual fire preset lets you jump with A, and it lets you technically jump and fire your gun, but you lose out on the ability to free aim while you’re jumping. This means you aren’t going to be as effective as bumper jumping.
From what we’ve seen in a lot of videos and feedback, people mentioned finding bumper-jumper slightly uncomfortable, but after a short period of time they got used to it. That’s a really good thing. If people are willing to try out bumper jumping, they’ll find out that it still plays very nicely. But I know that there are some diehard A-button jumpers.
Q: Any final thoughts you’d like to share with fans or readers?
Rogeles: I want to give a big thank you to everyone who downloaded the prologue and gave it a try. The feedback has been overwhelmingly positive. This has been something that we’ve worked on for four years, and we’ve shared it with the internet before, but we haven’t pushed as hard as we have these last couple of months. It’s incredible to the way players are reacting to the game. The biggest thing for me is seeing the smiles, the laughter, and the reactions. It fills me with joy.
I don’t think there’s a better feeling than seeing people enjoy the thing that you’ve created. I appreciate those who gave us feedback, positive and negative. It ultimately serves as a way to help us make the game better. I appreciate each and every one of you.
Elizalde: I just want to thank everybody that’s played it so far, and anybody that plays it, and hopefully more people give it a chance. The reason we made this game was just to be able to bring joy to people. That is our hope. We just hope that you like it and that you enjoy it. Nothing fills me with more satisfaction than knowing people are really enjoying something that we worked so hard to make.
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BioGun is in development and will be available on PC.