Hit the switch to open door/destroy wall.
The catch of the second level is that stepping on gray tiles kills you, right? Although I think the ambiguity of the puzzles adds some thought provoking to this, I feel like most people will never get that and just rage-quit early on lol
So maybe easing into more ambiguous stuff is the way to go with something like this
Also how the heck do you beat level 5 LOL
I swear I've tried every thing; it's killing me D: