2 Player Galaga:
For a 2 player Galaga, hold Up + L1 + Triangle + X on controller 2 while the game is loading.
Play As Devil Kazuya:
Not an easy cheat but a rewarding one, nonetheless. Perform the 'double firepower' on Galaga (for an advantage) then you must get a perfect score on all 8 bonus stages. Now at the title screen, choose 'arcade mode'. When the player selection screen appears, highlight Kazuya & select him with the Start button.
Play As The Boss Character:
Select a character & beat all opponents, including Heihachi. When you restart, go to the character select screen & select the boss you just beat by moving the cursor off the screen.
Email me: email@example.com