Solving a puzzle in a non intended way is a great moment. I did manage to move one corpse out of the pit. But this did not solve the puzzle.
Also, figuring out that corpses could be moved at all is a leap in solving. The first time you need this, is lvl 7.
Stuff like that can also be used to create two versions of a level. First the obvious intended solution. And later you make the easy solution impossible by a little change.
Lvl 8 I solved with momentum. But then I realized I would not need that mechanic.