This game is the Othelo version for iPhone.
Revert is a two player game, and is normally played on a 8x8 grid. The object of the game is to fill the board with your own colour of pieces. You win if at the end of the game there are more pieces of your own colour on the board than your opponents. The initial setup of the board is two pieces for each player, placed diagonally to each other in the centre of the board.
Each player in turn places a piece on the board, starting with the player using the green pieces (human player). A valid is one where you can turn at least one of your opponents pieces into a piece of your colour. You can do this if when you place on the board, it terminates a continuous line of pieces of the opposing colour, with one of your pieces at the other end of the line. All of the pieces in the line are then flipped to your colour. The lines can be in any of the eight lateral and diagonal directions from the position you have chosen. If there is more than one such line of pieces, all of them are flipped to your colour.