Invisible, Inc. is a tactical turn-based strategy game by Klei. I played it on the Mac and it's a great stealth strategy game. If you like the Go series, you will definitely like this game. It's similar in that you are trying to avoid detection and that each level is a puzzle to figure out. But the mechanics of Invisible, Inc. are much more robust and the solutions to problems are not quite so linear. There are multiple difficulty settings and the tougher AI can be pretty brutal. It was one of my favorite games of last year. I will probably double-dip and buy it on the iPad. Obviously I haven't played it yet, but it's an isometric TBS game so I would imagine that the controls will translate just fine to a mobile port. And it's Klei, pretty much everything they do has a lot of polish to it.
https://itunes.apple.com/us/app/invisib ... 31964?mt=8