Web workers are atrocious though. They're very strangely hobbled by either requiring a serialize->deserialize round-trip when passing data back and forth, or you can sidestep it by 'transferring' the object across contexts (it then 'disappears' in the original context). The reasons for doing it rather than sharing are obvious (the race conditions would be hard to track down, etc.) - but there's no escape hatch for languages like ClojureScript which has immutable data-structures (and therefore don't care about mutable race conditions) and persistent/structural-sharing datastructures (and therefore would be very costly to serialize/deserialize, or totally broken by the transfer model).

Really a shame.

I ran the Quake 3 demo. It was frameskipping all over. Performance was not acceptable for even playing. I think 10-15 fps. No, its not my laptop. My laptop has no problems with real Quake 3. I want to ask you to take a step back and look at it purely from a black box perspective. Forget about JavaScript for a moment. Is it really your opinion this is reasonable performance?