The engine

Kuiper

Kuiper is the engine under our games. We wrote it ourselves in Swift and Metal, starting in late August 2026, and it carries no off-the-shelf game engine underneath. Twinfall is the first game to ship on it, and the ones after Twinfall are already being built on it.

• LanguageSwift 6
• GraphicsMetal, drawn directly
• SimulationFixed 120 Hz tick
• Display120 Hz on ProMotion
• First gameTwinfall

What it does

Kuiper keeps the game and the picture apart. The rules of a game run on their own clock, 120 steps a second whatever the screen is doing, and the renderer only ever draws what the rules decided. That split is what lets the rest work:

• The same inputs give the same run. The rules use a fixed step, seeded randomness and no wall clock, so a game can be played with no screen at all, far faster than real time. That is how we test difficulty: a simulated pilot flies a stage over and over, and we measure it before it reaches a person.
• Every frame a ProMotion screen can show. Kuiper drives its own Metal layer, so on an iPhone that refreshes at 120 Hz the game draws at 120 Hz too.
• Real 3D on a flat field. Ships are lit 3D models, while the play itself stays on a plane you can read at a glance.

Why write one

Our games are small, and we would rather know every line between your finger and the pixel than learn someone else’s. An engine of our own does only what our games need, so there is less of it to go wrong. It also gets better with each game: whatever one game teaches it, every game after it gets for free.

The name

Kuiper was our yellow Lab. After we lost him, Zeus and Luna came home, and they are the two dogs in our mark. The engine underneath everything we make is named for the dog who came before them.