I believe the lag could be mitigated by adding a tiny bit of frustrum culling and, if it’s not already here, object pooling! Cool idea, well done :)

I think the number of asteroids crashed my browser.

Apart from the lag, I think it's a well-thought-out concept.

Interesting and fun, if a bit laggy

swooshing through space is satisfying :)

though I thought the game was broken when I hit an asteroid and couldn't move anymore, now that I closed it I see that it was an intended effect