The game is great. My one issue is that I experience severe slowdowns in areas 3 and 4 of the second section, making the necessary fine-tuned jumps impossible.
Hm, that's a shame. I had a bit of slowdown in those, but thought I fixed it. How good is your computer, very roughly? I've got a fairly beefy machine for development reasons so it's hard to tell how much wiggle room I have.
