Good, With A Few Additions Could Be Great
Firstly, I put sound as 10 as didn't have sound on and so cannot justify a lower score.
Secondly I really liked the game, I felt it worked really well and it ran smoothly. Just a couple of suggestions to raise the score from a 4 to a 5. Checkpoints, instead of going back to the very beginning when you die there should be checkpoints at the start of each level.
My other suggestion is for more pick-ups, and also a "key" as such which tells you what each one does so one doesn't pick up a pick-up and find it kills them unexpectedly.
So those are my suggestions, other than that I felt it was a really good, yet simple game which worked really well.