All Weapon Mode:
Beat the game with any ending on hard with the 1 weapon mode.

Eileen's Sub-Machine Gun:
To unlock Eileen's Sub-machine gun beat the game in hard in a Brand New Fear File and get at least 9 stars. If done correctly: You can get the Sub-machine gun in your first visit of the Apartment World in room 102.

Chainsaw:
Beat the game once in any mode and Chainsaw will be available at the Forest (First) in the area where there's a car.