Originally Posted by cady1992
begin a game with an other profile on the level 3-5 ,before you kill the final boss press start on the second controller with your gamercard and finish the boss your second controller profile will have the PERFECT FIGHT achievement..
You can use a similar trick to get the easy, medium and hard achievements. You don't need to play through the whole game, just the last level. Sign in player 1 as your profile and player 2 as some other profile. Choose the last level (3-5) and play as far as you can with player 1, stopping before you use the last credit. Now hop in with player 2 and finish killing the boss up the last few shots. Now jump back in as player 1.
Each player will get the achievement for what ever difficult that profile has been set to. Also, when player 2 jumps in, that player will be given extra credits for what ever their profile is set to, even if player 1 is playing the level on hard.