Rock'em Sock'em Robots Arena Codes -

Fight as Old Red:
To play as the original red robot, win career mode as the Red Rocker.

Fight as Old Blue:
To play as the original blue robot, win career mode as the Blue Bomber.

Fight as Ben Hurt:
Win the career mode as Slamuri.

Fight as Sir Haxalot:
Win career mode as Head Case.

Fight as Tywrenchula:
Win career mode as Stakeout.

Fight as Blasto The Clown:
Unlock Sir Haxalot. Select versus mode, and fight as Sir Haxalot versus Stackout on upgrade mode. Win the match. Then fight as Sir Haxalot versus .X-Cavator on normal. Win the match to unlock Blasto The Clown.

Hint: Extra arms and legs:
Start a match in career mode and keep hitting your opponent's arms or legs until that piece falls off.