At the character select screen, place the cursor on Spiral, then hold it there for three seconds. Then put your cursor on these characters in the following order: Silver Samurai, Psylocke, Colossus, Iceman, Colossus, Cyclops, Wolverine, Omega Red, and Silver Samurai. When you stop on Silver Samurai, wait for three seconds, then press Light Kick, Hard Kick and Hard Punch simultaneously. If this is done right, the announcer will say "Silver Samurai", but Akuma will drop down and take his place as your character.