UNLOCKABLE: Mega Man Outfit
It was originally believed that the Mega Man outfit was obtainable if you were able to locate a particular toy store in the mall that housed the costume. However, unlocking the outfit requires some good old elbow grease, better known as hard work. You must unlock certain achievements throughout the game in order to piece together the outfit.
Real Mega Buster: Obtain the Zombie Genocide Achievement by defeating at least 53,600 zombies. This buster shoots actual destructive blasts opposed to the tennis ball cannons located in toy stores.
Mega Man Tights: Obtain the Punisher Achievement by defeating 10 psychopaths, or bosses throughout the game. You will know you defeated a psychopath when you earn a "defeated psychopath" message after a boss battle.
Mega Man Boots : Obtain the Unbreakable Achievement by getting the true ending of the game in the 72 hour mode plus the overtime mode without getting caught by the special ops. If you are caught by the special ops forces after the 8th case, or in overtime mode and you witness the sequence where you must wiggle out of the binds and escape then the "true ending" won't occur and you won't receive the boots. If you do get caught, restart the console and try again. With these boots on, items in your inventory are unbreakable.
Mega Man Helmet: No Achievement is necessary, instead all that is needed is a trip to a toy store. You can find the helmet in the toy store that resides in the movie theater, just north of Paradise Plaza.
Please Note: Once you attain each of these achievements, the corresponding pieces of the outfit will be delievered to the Security Room. You will find them behind the airshaft where you first meet Otis the janitor and get the map (plus the transceiver).