Great job with this! your levels were well thought out, I felt that the difficulty progressed at a good pace. The sound effects were up there with the best.
I had a couple issues with the jumping mechanic, especially on the stairs. If there was a ceiling and I was trying to go up the stairs I would hit the ceiling then fall before I could get up the step and got stuck on the ledge couldn't move, and then would fall back down.
I loved the upgrades, and the sprite designs for everything. Great job with all the artwork.