I looked at the source - they are using Hipmunk for the physics engine, a Haskell binding to Chipmunk (a physics library in C) to store state like object positi

I looked at the source - they are using Hipmunk for the physics engine, a Haskell binding to Chipmunk (a physics library in C) to store state like object positions. Things like updating positions of objects occur in the IO monad. The UI is done using a custom Qt Haskell binding, and it looks like the key mapping to key translation is hard-coded - possibly the cause of key problems on Mac if they key codes are different to what it is expecting.