Gunstoppable: How "Speed Is Damage" Defined a Roguelite FPS

Gunstoppable is built around the idea that "speed is damage." How did that core concept shape the earliest prototypes, and when did you know the movement system could carry the entire game?

My recent career has centered on movement, from my work on God of War's traversal, grapple, and vehicle systems, to my previous indie title Sherwood Extreme, built around parkour archery. In fact, my earliest prototype for Gunstoppable didn't have weapons at all — it was a game about a monkey climbing a tree, called Banana Rush. I eventually added weapons to amplify the stakes and possibilities.

Although movement was always the focus, I didn't think of the "speed is damage" hook until I showcased it at a public convention. As I described the momentum-fueled combat, one player said, "Oh, so you deal more damage the faster you move?" That sparked a flame, and I created systems that turned speed into a resource that can be built and consumed for combat capabilities.

Your background includes work as a Gameplay Engineer on God of War Ragnarök, specifically around movement mechanics. What lessons from AAA movement design carried over into Gunstoppable, and what had to change when building a much faster, more exaggerated roguelite FPS?

Working with a large, talented team showed me the range of depth and intentionality that goes into every invisible but tangible aspect of satisfying movement — from input tuning to camera design to animation, UI, and playtest iteration.

God of War Ragnarök puts a particular emphasis on weighty impacts and visceral melee combat. While I leveraged the same frameworks for movement in Gunstoppable, my goal focused on player freedom and fluidity, overemphasizing individual actions. For example, the grapple into wall-run movement can be used nearly anywhere, with weighty but smooth impacts and transitions, compared to the more hand-crafted and individually tuned abilities in Ragnarök.

Movement is one of the most repeated inputs in almost every action game, but it is also one of the hardest things to make feel "right." How do physics, acceleration, friction, camera behavior, input buffering, and animation feedback all work together in Gunstoppable?

The key is to form an intentional goal for how and why movement should feel a certain way based on the style of the game. Then, take inspiration from real-world physics and other games, but bend the rules to make them fit the desired feel. Getting it all to feel juicy is the final piece, using visual FX, camera tricks, and animations to sell the impact and responsiveness. Interactivity — from input to response — is the cornerstone of a fun game.

Playtesting is the only way to validate that the desired feel comes across. As a Solo Developer, I rely on my community to steer me in the right direction. I gave a GDC talk this year about movement, which is free to watch online, for those interested in more details.

Gunstoppable combines boomer shooter speed with roguelite progression, overpowered weapon combinations, and "break the game" upgrade stacking. How do you balance that sense of chaos with enough structure and readability for players to stay in control?

I introduce mechanics gradually over the course of multiple runs to balance chaos with readability. What starts as a simple movement shooter evolves into mayhem as upgrades are intentionally chosen, one by one, until the player becomes a blazing trail of firepower. Pacing is a challenge for games like these, but careful tuning can make the action palatable even for new players.

Even so, early builds of Gunstoppable found players getting lost in all the action. That's where the visuals and audio play an important role. Adding visual contrast and distinctive sounds to the most important gameplay elements helps players subconsciously map their surroundings in the midst of fast-paced action. The result is described by many playtesters as a type of "flow state" that captivates their attention without feeling overwhelming.

The game is a solo-developed project, but it also has a fully voiced story campaign, bosses, multiple environments, procedural run variety, and a strong combat identity. What does your production pipeline look like, and how do you prioritize what to build, polish, or cut?

Production planning has been at the forefront of my mind since day one. I set out to ship the game in under 2 years and have remained on track. What I've learned from my previous 3 indie games is to structure the production to allow for a full prototype to be completed quickly, while leaving room for content to be created indefinitely.

For Gunstoppable, I started with a one-month prototype that proved the core mechanics are fun and worth pursuing. Then, I created the 4-act structure with very few weapons, upgrades, enemies, and levels. I spent the next 6 months adding as much content as possible, then spent the final 6 months iterating on it to balance difficulty, tension, and variety. This production structure encourages me to prioritize the most promising features to stay on track.

What engine and tools are you using for Gunstoppable, and what custom systems did you need to create for movement, combat, procedural runs, weapon upgrades, animation, VFX, and performance?

I'm using Unreal Engine 5.6 for Gunstoppable, Blender for custom 3D models, Audacity for audio editing, and DaVinci Resolve for video editing. All free software. Nearly all gameplay features — movement, combat, upgrades, graphics, audio — are custom-built by contractors or me. The software only provides a framework for creation; it's up to the developer to envision and build the actual game.

Unreal Engine games often get flak for poor performance, but I used their built-in tools to pinpoint where performance could be improved, focusing my efforts to get smooth framerates even on 10+-year-old machines.

The game's story frames the player's rampage as something going viral worldwide, with rogue robots, evil billionaires, and a kidnapped sister. How did the game's satire and tone influence the art direction, enemy design, UI, music, and overall presentation?

I wanted the story to reflect the over-the-top gameplay, while leaving room for a surprising amount of emotional depth. I've always been drawn to dystopian sci-fi worlds, yet I often found them dark and rainy, rather than bright and colorful. It's the juxtaposition of bright colors and comedy with family trauma and capitalist nightmares that creates Gunstoppable's identity. Even the gameplay mimics this, contrasting player freedom and choice with chaotic and randomized encounters. Satire lands in the fine line between deeper meaning and silliness.

For 80 Level's audience of developers and technical artists, what has been the hardest part of making Gunstoppable feel fast, readable, and responsive at the same time, and what advice would you give to anyone trying to make movement the heart of their game?

The most difficult and yet most important part of development is actually listening to player feedback. Nobody wants to hear that the movement feels floaty and clunky after investing 6 months trying to make it a defining feature, but if I didn't get those nasty comments and harsh demo reviews, I would never have pushed myself further and further to refine the crisp movement that I have now.

Time and time again, I see developers, big and small, developing in the dark. They think they, as developers, know better than the players themselves. But you need to find strangers, not friends or family, who will not hesitate to tell you why your game sucks (for now). Even the God of War team runs public playtests years before launch. I would never have found the fun without my generous community, or without haters on the internet.

Salaar Kohari, Founder of CAGE Studios

Interview conducted by David Jagneaux