Unfortunately the fullscreen key doesn’t exist as a stand alone key on my German keyboard. You can activate a fullscreen button for browser games in the itch backend, I don’t think it would be against the rules to still activate that.
Anyways… Really cool what you achieved with the limited 3D capabilities of C3, I especially liked the effect of the glass that became more opaque the more you looked at it from an angle. I don’t know if it was intentionally or not, but the thing I liked the most about the game is how OP pacifist runs are :D Not only conceptually as some fun contrast of expectations, but it is simply really fun to play it that way too. You gotta speed through the level always moving to not get shot, strafe jumping through the air :D Great entry.