It was pretty brilliant. reminds me of the old arcade games, however what I don't like about this i the ships that go from behind. it's irritating for a player to get surprised by them and will almost guarantee that to pass that level you need to retry it many times to know where those surprise atacks are.
you can just refresh and it'll go back to normal; but normally I think it's 35 for windows, 140 for mac, and ~200 for linux