Well if you can remember what genre it was, you can check that category.
Also, you may be able to find it if you search for words related to the game. For example, if the game had zombies in it you might search zombie, gun, etc
Like Green said, you could use the search function.
Or, if you think you would remember what its called if you saw the name, you could click the "history" button at the top. Then click "show all history". It should show what you have done recently, so just scroll until you find the game.
