Originally Posted by pahncrd
It won't play, the 2g devices use a much weaker graphics processor.
In fact, it is the fact that devs have to still target the old devices for performance that keeps iOS game graphics held back (budget is a factor too though). Though, things are gradually getting better as more devs are willing to leave the three year old devices behind.
Three year old devices? Sixteen months ago, the newest iPod Touch available was the 2g.