HTML5 games are still a bit too slow for me. I'm on a modern machine, but if I'm doing a heavy compile in the background it shows how slowly HTML5/canvas rendering actually is. [If it could only start using my GPU?]
I'm not sure if Flash uses my GPU, but it's fast enough so that I can play a similar game while doing background compilations.
Although after playing a few levels, the game is partly to blame. It's far too easy to die - I don't think I've had more than a few seconds of play before dying and having to restart. Gets frustrating.
The game has great physics and fun game play, but it fails socially. It really needs a few learner slopes to start with that introduce the concepts.
Crowd-sourcing of track design is a great idea, but the game needs a better way to filter out the crud. Most of the designs are personal experiments, and even the better ones could really use a few checkpoints.
I'm not sure if Flash uses my GPU, but it's fast enough so that I can play a similar game while doing background compilations.