mazefinger nearly unplayable on 1G ipod touch

The last 3 updates or so for Mazefinger have caused the game to perform really bad on my 1G iPod touch. I'm surprised this hasn't been reported (if it has, I couldn't find anything, except my own post from a few months ago) because it's hardly playable anymore. I know for a fact that the updates have caused these problems, because the first version i got from the App Store worked perfectly. My iPod is not jailbroken.

Please don't recommend getting a newer iPod touch model, it's not an option for me right now.