Maybe I need more sleep but It made me feel a little motion sick, I can't explain why though. The music is great although I didn't hear much of it because I never made it very far before the I died and the track restarted. Which in some ways could be considered a motivation to keep playing but in this case wasn't enough for me so I became irritated the more it restarted and eventually I stopped playing. This was also due to the fact he slimes and the jump are not as well balanced as they could be. I feel as though either the slimes are too big or the jump is too weak.
I loved the character sprite, the jump animation and the death animation however sometimes after dying I would still be moving and one time it went on for so long I saw the end of the map which made me even less likely to finish playing.
Overall the game looks amazing and with a few tweaks you have got a game which is really good.