Resident Evil: The Directors Cut

Hidden ammo
In the beginning of the game after you go through the blue double doors and the brown one there are two moveable display cases, after you shoot the two dogs go to the one around the corner of the door you came in move it and you should find a 9mm clip. (Not much help but in case you want to practise controlling your character while shooting that way you can get the most shots at a zombie more quickly so they won't get very close to you.)
 will save you a few rounds of valuable ammunition.

Save some ammo and health
When you are playing as Jill and you enter the dining room. Go to the fireplace and after the scene go back through the door you came in. After doing that go back through again. After that scene go back through again and the screen will say"there may be more here worth investigating. Now go down the side of the room with the clock if done correctly azombie will come out and a scene with Barry killing the zombie will happen saving you some ammo and the risk of going in the corridor with the zombie.

Hunting Tips
To kill Zombies in one shot, let them walk right in front of you. Then aim high with the Shotgun and fire. Poof! Dead zombies. For acid-spitting zombies, let them get pretty close, then fire three steady shots with your Beretta. This will save you a lot of ammo. To kill spiders quick, here's what to do. If you're Jill, arm the Bazooka with Flame rounds. Then when you encounter a spider let it get pretty close (or if you like, when it's ready to bite you), than fire! This works only agaist medium-sized spiders. You can try the Acid rounds, but it might take a shot or two more. For Chris, if you can pick up the flamethrower, use it against the huge spider.

Double items
On the game mode screen, highlight the Arrange option and hold Right until the pointer turns green. Then, begin a game and double the normal amount of items, including ink ribbons and ammunition, will be available.

Rocket launcher
Finish the game in under three hours without rescuing anyone. If done correctly, a rocket will appear after the credits. Then, choose to continue playing after the game restarts. Now the rocket launcher with infinite ammunition will be available when the new game begins. Note: The rocket launcher does not shoot well upwards or downwards.

Magnum
Finish the game on advanced mode as either character in any amount of time. Then the Magnum, with infinite ammo will be available when the game is replayed.

Other Costumes
Rescue the other two players and finish the game. If done correctly, the phrase "You've got the special key" will appear after the credits. Save the game. Start the game that was just saved. Enter the room with the large mirror on the second floor of the mansion. Unlock the door in the back. Enter the closet and move all the way to the end of the rack of clothes. Then, a message asking "There is an outfit that fits you perfectly, do you want to put it on?" will appear. Now select "Yes" to change your character's clothes. Note: When playing the game with the "Arrange" option, your character will not have the key, but the door will be unlocked.

Reset game
Pause the game and press Start + Select.