Oceanhorn
Is a big game with lot of graphics.
Currently playing XCom - Enemy Unknown on my Android Tablet. Very complet and smooth game (3.6 GB of download).
Time spent on it right now: 4 hours (only playing on my way to work and back home)
I'm not generally a big mobile gamer either, but I have spent a *lot* of time on Pixel Dungeon. It's an incredibly well-designed little game.
I have to second a few already
X-Com Enemy Unknown
Horn
Knights of the Old Republic
Grand Theft Auto Series
Galaxy On Fire 1/2
DemonHunter
Aralon
RavenSword
Bastion
Street Fighter 4
The Simpsons: Tapped out! ... has grown really big as well.
Not very much gameplay, but heaps of content!
Develop games in your browser. Powerful, performant & highly capable.
In my opinion all AAA titles that have been "adapted" for mobile are super complex, but thats kinda obvious isn't it...?
I would have to say a big/complex game is `Beastie Bay` and `Game Dev Story`. I have beat them but it basically has infinite replay value. Or if you wanted a fps there is `Modern combat 4`. It's great but you will want a moga controller for it. If you are wanting a mmo `Order & Chaos Online` is the way to go. There is a pretty big player base and they constantly add new content.