Unlock two costumes in the Boutique: Beat the game on the Easy difficulty with any ranking.

Unlock all costumes in the Boutique: Beat the game on the Hard difficulty with an A ranking.

Unlock Assualt Rifle with infinite ammo: Purchase for $2000 in The Mercenaries: Operation Mad Jackal minigame.

Unlock Gatling Gun with infinite ammo: Purchase for $3000 in The Mercenaries: Operation Mad Jackal minigame.

Unlock Rocket Launcher with infinite ammo: Purchase for $5000 in The Mercenaries: Operation Mad Jackal minigame.

Unlock infinite ammo for all weapons: Purchase for $9999 in The Mercenaries: Operation Mad Jackal minigame.

To unlock the minigame, The Mercenaries: Operation Mad Jackal, you have to bet the game once, and then save over with the 'Next Playthrough' option. Once you have done this, enter 'Load Game' and load the 'Next Playthrough'. An option will come up about what you want to load, and one of the options will be The Mercenaries.

In this minigame, you choose between Carlos, Nicholai and Mikhail to play as, and you have to get from the tram to the warehouse in a limited period of time, or you will explode. Each character has their own set of weapons and healing items. Killing enemies adds to your timer, as does rescuing hostages.

Playing this game can earn you money to spend on special infinite ammo options for the main game. Plus, it's good fun.

Okay some people may know this if they got the Versus Books guide. When you get to the part with three zombie dogs after two Hunters. Kill two of the dogs and climb up onto the stack of wooden things. Get kinda close as the dog tries to jump at you and start tapping dodge and you'll get all sorts of time and money. Then you can do it for a long time and when you get like 99:99:99 kill the little dog and run like crazy to the end XD

When walking behind a monster, keep tapping run quickly. Jill will be "gliding" and will not make any footstep noises so the monster will not turn around and attack you.