Blitz! by Trivial Technology is a fine card game for those who are into such games. If you're not familiar with this one, you'll want to read through the instructions first. The idea is to have a three-card hand that equals or is closest to 31 where aces are 11 and faces are 10. Five strikes and you're out. The game generally has four players, which are all there in a single-player game, but multiplayer can pit you against 1-3 other players besides yourself.
As with any card game, as long as you have the math right, the only thing left to grade is really the graphics and presentation. And in Blitz!, they do them just good enough. They're nothing to write home about, but they work. The only issue is that you are always taking out one card from your hand by tapping it, and if you're not careful, you could tap the wrong card.