In Dead Rising 2: Off The Record for the PC, PS3, and Xbox 360, the Protoman Costume is similar to the Megaman costume from Dead Rising, but with a strong attack that shoots three blasts.
To unlock the Protoman Blaster & Shield, you need to beat the game with an S Rank by beating Overtime mode.
Check out my other guide if you’re looking for the rest of the Protoman Costume pieces.