After you have become a Ro-Bro on the last stage of the game keep going left until you reach the left side of the screen. If you now go down you will descend a hidden ladder where you can find multiple 1-ups and two unlockable chests.
Punch the heavy bag in the glass cell where you start in Level 7: 'Some Kind Of Lab' exactly 87 times. You will then hear a chime sound and be teleported to a different area of the stage which will be full of enemies, traps and platforms. Your head will be replaced with Roper's and every character, including the Lee brothers will ALL have Yoshihisa Kishimoto's face instead of their normal face and once the area has been completed you will get the secret Achievement 'A Foot Face?'.
To set Fuzz Face free you you must dodge seven times between the two tombstones next to the ladder in Level 6: Assault Zone. Fuzz Face will follow you and drop Dragon Kick and batteries roughly every minute making the game a lot easier.
At the 'Level' selection screen hold LB + LT + RB + RB + Back + Start + click Left Analog-stick + click Right Analog-stick to play as Ro-Bro. If the code has been entered correctly you will hear a confirmation sound. Input the code again on the same screen to revert back to normal. This code gives you the robot form costume without the extreme power up.