Very good, but a few bugs
Like someone said before uphill and downhill enemies are impossible to kill. On the jungle level right after you leave the water, the crystal only appears *sometimes* where it's supposed to. I also fell staright through an enemy after a drop and lost a life in the process. On the ice level, there's no way to reach the floating springs and the three top eggs of that small clutch of nine are unable to be collected. Also, if you die on the lava level, when you come back, you still have no lives and therefore come back in time to die again. Not sure about anything past that point.
Other than that, a very good job.