Do the powerups come while you're playing the actual game? And then only stop when the game should have stopped, or do they not come the whole game through? Is the bar on the top full, when the game ends? Is it like a normal game until it should end(ball waves come, powerups come etc..?)
So how do you know that it's the menu? Do you see the Play Button, or the Achievements Button, or the More Games Button? But the Computer on the top is still playing?
That bug occured, because there was a security.domain issue in the version v 1.0.5.
It should all work fine with the version v 1.0.2 (Clear your cache if you're playing any other version)
You can see the version you're playing in the top right corner.