Reversi - Othello play online

Reversi (a.k.a. Othello) is a board-game based on a grid with eight rows and eight columns, played between you and the computer, by placing pieces with two colored sides. This application is free and without any advertisements.

Game features
Powerful game engine.
Hint feature: the application will suggest next move for you.
Undo last moves by pressing the back button.
Gain experience points (XP) by earning game achievements (sign in is required).
Compare your score against other players on the leaderboards (sign in is required).
Import/export game on local and remote storage.
Game engine performs multiple moves in case you have no valid place to go, due to the well known rule "If one player can not make a valid move, play passes back to the other player".

Main settings
Level of difficulty, between 1 (easy) and 7 (difficult)
Select player mode: application AI as white/black player or human vs. human mode
Show/hide last move, show/hide valid moves, show/hide game animations
Show emoticon (active only during last part of a game)
Change color of game board
Optional voice output and/or sound effects

Game rules
Each player must place a new piece in a position that there exists at least one straight (horizontal, vertical, or diagonal) line between the new piece and another piece of the same color, with one or more contiguous opposite pieces between them.

Black color starts first move. When player cannot move, the other player takes the turn. When neither players can move, the game ends. The winner is the player that owns more pieces.

Dear friends, consider that this app doesn't contain advertisements, in-app purchases, so this app will evolve depending on your positive ratings. Be positive, be nice :-)

IMPORTANT NOTICE FOR BEGINNERS: our game performs multiple moves, as any similar application, only in case you cannot move as you don't have any valid place to go, i.e. when you have to pass your turn according to well known game rule "If one player can not make a valid move, play passes back to the other player".


Permissions
This application requires the following permissions:
INTERNET - to report application crashes and game related diagnostic information
WRITE_EXTERNAL_STORAGE (aka Photos/Media/Files) - to import/export game on filesystem

In case you perform the optional signin, the Reversi application can access your Google Play Games profile.