MindLab I love puzzle games, but...
I guess I'm really just going over the same things others have said at this point. The collision detection got really bothersome. Multiple times I got to the end of a stage only to try to walk through the last gate to the cheese, and suddenly I was irreversibly caught on a nothingness by the gate only to have to restart. Mix that with being killed by being in the general vicinity of the traps and it just became too frustrating. Plus, mixing the collision detection with slippery walking physics only exacerbated the problem.
I really like the idea, and aside from the collision detection it was a fun game! The music was fitting, the puzzles pretty interesting and the concept good. Keep it up!