This game will freeze on you after beating just one level if played on Chrome. Looking back at the comments I see this problem goes all the way back to when this game was released and game author would rather tell people to update their Flash (not at all what the problem was) rather than fix it.
You must play this game on Firefox even though it plays choppy and not at all smooth there. You actually can get past the stages and earn the medals if played on Firefox.
Also the old arcade games were not laggy and choppy like this! I'm tired of "retro" games that aren't even as good as the actual retro games. And those used much less capable hardware than what modern computers offer.