Thanks for the comment! Unfortunately this is what we are left with past Flash era ¯\_(ツ)_/¯ - games work differently on different browsers. So far only webkit browsers been able to run it smooth enough, but GPU is factor there too.
Works much better in Chrome! Wow, very cool. I like the destructible levels. I think adding a few different guns, and maybe making sure the height of the rooms is a bit taller, would vastly improve gameplay!