Thanks! ❤️ Yeah the 18th level indeed seems to be the biggest hurdle for most people. Still kinda happy with the difficulty curve, at least it's one of the last few levels. And super happy I was so lenient with the level skip system. 😅
There is this wall crushing/collision detection thing in place (mainly for the mario level elevators). It can sometimes be triggered in other places too while grinding against the walls too much or at great speeds. There is an hp system built around it too so you need to trigger the collision several times before you manage to kill yourself so it should be quite rare.