In the Combat Simulator, turn on two players and have the first one go to the challenge you would like to select. Then, have the second one prepare to choose a save file from the memory card or game pak (preferably an easy one). Select the challenge you would like to complete on the first one and then select the save file on the second one. The game will substitute the challenge with the save file and instead of playing the challenge, you'll be playing the save file. Make sure teams are enabled and that there are at least two teams. Once you complete the challenge, it will give you credit for completing it and it will play as it normally would.
Submitted by: Glitched Symbols