In Memoria, both players will have to clear a shared board by finding the pairs of shapes behind the spinning squares, as score is added for the pairs of shapes unlocked. The one with the higher score wins.

Simply click on two of the squares whenever it is your turn.

You win by unlocking more pairs than your adversary.

1) When a player clicks on the square that shape will be temporarily revealed. In higher density boards, it will be hard to memorize where they are but keep in mind that you should both pay attention to the shapes revealed by the other, as you may be able to complete a pair immediately in the next turn;
2) The higher density board is very difficult, try going for less squares on the first games so that you grow familiar with the shapes to instantly recognize them – this game is about making quick decisions based on your memory, so don't take too long between choosing the first and second square as you may give your game away to the other player;
3) Remember that you do not get more than 2 clicks per turn, make them count.