Note: May not be valid for subsequent Xbox patches. Acheivments in the game can be obtained by someone else, but applied to your gamer score by playing in co-op. The trick requires two friends playing co-op frogger. First, begin a co-op game with someone who is good at the game. They must host the match. Then, have your other friend host a private co-op match and send you an invite to it (don't accept it just yet). Play through the co-op game; it does not matter if you die as long as your friend obtains the criteria for the achievment. As soon as he meets the criteria (i.e. beats level 5), accept your friend's invite before he loses all his frogs (join GAMER 2's game while GAMER 1's game is still going) Since you have now switched from the left hand screen to the right hand screen (because you are no longer hosting), the game thinks that you completed the achievments which your friend actually did.