Invisible Wall: It looks like this is what I found.
Cheat code: when you press R, the level reloads, so it makes no sense to press in turn (although I tried), and tried to press everything at the same time.
2 years ago(+1)
Perhaps your keyboard only supports up to 4 keys pressed at once? I've seen that before very occasionally.
Yeah, R should only restart the game if you're not holding the other keys!
Strange! Thanks for letting me know anyway, next time I'll make the cheat use less keys!