For all unlockables, you need to earn an ending. If Frank dies, you fail to earn a required ending, or you choose to start a new game after meeting the requirements, you do not unlock the reward.

Ammo Belt (costume) ... Do not miss with a machinegun. If you miss, start with a new (150 round) machinegun.

Arthur's Boxers (costume) ... Survive for at least 7 days in Infinity Mode.

Hockey Mask (costume) ... Photograph all PP Stickers.

Real Laser Sword (weapon) ... Survive for at least 5 days in Infinity Mode.

Mall Uniform ... Answer all calls from Otis.

Mega Man Boots ... Get the best ending without being knocked out (you can load a game if Frank is captured or killed). You get this achievement by finishing Overtime mode not 72 hour mode. -- XOsgrayX (IGN)

Mega Man Clothes ... Defeat at least 10 psychopaths.

Prisoner Garb ... Steal the convicts' jeep.

Pro Wrestling Boots ... Break 100 items (this means use until it disappears, not throwing them)

Pro Wrestling Briefs ... Defeat 1000 zombies without any weapons. Most skills are considered bare-handed. Not all melee attacks count! Big swing, hammer throw and lift up don't count! The moves where you use a zombie to kill a zombie are not considerd bare handed moves. --wholycrapon (IGN)

Real Mega Buster ... Defeat at least 53,594 zombies in one session.

Special Forces Boots ... Defeat at least 15 psychopaths (or 10 special forces soldiers).

Special Forces Uniform ... Destroy the Special forces helicopter (Mega Buster or Machinegun is best).

White Hat ... Photograph at least 50 (living) survivors.

Submitted by H-911 WOLF (obeljaykobi)