ElyGo is a complete Go game app (Igo Baduk Weiqi) for enthusiasts. This is the lite version and has several limitations over the full version but it lets you try most of the features for free !

Full version : http://goo.gl/okJ71z

Features (full version) :

- 500+ built-in Tsumego problems with answers as well as bad variations
- Play against a bot (GnuGo 3.8)
- Play and observe games online on IGS (full version only)
- No ads even in the free version
- SGF Editor to review and edit games
- Loads Kogo's Joseki Dictionary
- A challenge mode where you have to solve a set of problems in a limited time
- A database of 20 000 pro games
- Import your own game database
- Comes with 3 visual board themes
- 3 different ways to play stones on the board
- Automatically loads .sgf files opened from another apps (full version only)
- Prevent device standby while playing or observing games (this can be disabled)
- Automatically zoom and rotate problems to use the maximum space on the screen (customizable)
- You can review your own game collection (like commented pro games) very easily
- You can choose your color in problems (black white or random) and change several other settings