Really nice. I realised during lvl5 I could play with a gamepad, the game became a lot more enjoyable after this aha! The game is still pretty hard. Some of the levels have more than one "stage" to solve, so when you die just before the end, you have to solve everything again. I think you could split some of the levels in two (or add check-points maybe).
Also you can skip the whole level 7 if you jump over instead of going in the pit where stalactites falls. Was that intended?
But hey, I'm just quibbling, I enjoyed playing it, good job.