Pretty fun. The music loop got super annoying real quick, but there are mute buttons for those sort of things.
I occassionally got a bug where the screen flickered blue, as if it got constantly reset. It got fixed by refreshing the page, but there was nothing else that worked. Also annoying is the fact that TNT barrels seem to only explode when they hit the ground, but not if they hit enemies. Might be intentional, but it was a bit annoying.