Well, you could put a bit more work into this. For example during the deathmatch me and all bots/helicopters were suddenly locked in some kind of a stasis with no option to move either way and the timer stopped running. Also, I admit, that the game is a bit heavy to handle by a browser.
PS
About the stasis issue: the same just happened to me during wave 5 of zombie survival so no, it is not a computer issue but a problem with the game.