I had no issues with lag, but you seem to have gone out of your way to make the second stage as much of a pain in the ass as possible. I liked the music. I liked the artstyle. I even liked the premise.
Can't beat it though, because I can't stomach falling over... And over... And over again. Designing a good game means giving players a challenge that is tough, but also, fair, and I believe that that is what's lacking most here. Overall though, it's a good game. Don't give up!