that's probably because Malerouille might be used to AZERTY keyboard layout, and the issue only happen on QWERTY layout. A suggestion: have crouch/sneak on a 'toggle' instead of a 'hold' mode.
Hahahaha no i'm sorry, i make 3D Geologic data visualization software libraries, but i WISH i worked in indie game development ! :P I try on my spare time but corpo work suck the life out of me x)