This game is awesome, I've purchased a bunch of more 'in-depth' iPhone games but I've had the most fun with this one. I would definitely suggest trying it out.
I think that the games that are successful on mobile devices are the ones that best understand the platform. A port of an existing PC/console game will invariably be difficult to use or have compromises. Games that are quick, easy to learn and utilise the platforms features are most likely to succeed.