Use the following trick to unlock all the costumes pieces without having to 
replay a level repeatedly. Play a level that unlocks the desired costume. Just 
before the level ends, select "Option", and save the game on file A. Complete 
the level to get a random costume piece. Then, save the game on file B. Load 
save file A, and you will be back on that level. Complete the level again to get 
another random costume piece. Save the game on file B, load file A, and repeat 
until all costume pieces are unlocked.