My suggestions for Android gaming (and I'm biased towards skill games, so <.<) are:
Rhythm games:
jubeat plus (the iPad version is better, if you ever get a chance. BTW, I think this is only in the japanese google play store, so you might need to fiddle with stuff)
Cytus and
Deemo (Rayark isn't the best at rhythm games, but - they're playable, they come with a ton of songs for free, so I am obliged to recommend nonetheless)
Beats (Stepmania for Android)
Shmups:
http://shmups.system11.org/viewtopic.php?f=1&t=43212
All the ones he lists are good. There are (or should be) Lite versions for all of them, so you can see if they feel and play right before shelling out money. I've been enjoying Espgaluda II lately.
I also hear there is MAME for Android:
https://play.google.com/store/apps/details?id=com.seleuco.mame4all
I have no idea how well it works, but if it's good, that will open up a huge amount of games available.