Resident Evil 4

Each weapon has a special "Exclusive Power" when all of its stats are custom tuned to the maximum:

Blacktail - Increases firepower to 3.4
Broken Butterfly - Increases damage to 50.0
Handgun - Increases the chance of a headshot being fatal by a factor of five (5% or 20%, take your pick)
Killer7 - No exclusive power
Matilda - Increases magazine capacity to 100
Minethrower - Adds homing ability to mines and increases their blast radii
Punisher - Each bullet can penetrate up to five bodies
Red 9 - Increases firepower to 5.0
Rifle - Increases firepower to 18.0
Riotgun - Increases firepower to 10.0
Shotgun - Increases the effective damage range of the gun
Striker - Increases magazine capacity to 100
Semiauto Rifle - Decreases firing speed to 0.40 seconds
TMP - Increases firepower to 1.8

Wait until you are low on ammunition before upgrading a gun. The replacement gun will always have a full clip, giving you extra bullets that otherwise may be difficult to find.

During the part where Leon and Luis defend the cabin, shoot Luis with your pistol (or any other gun) around 8 or more times. You will get a cut scene where Luis will shoot Leon back, and give you a game over.

To find items, smash all of the crates with either your knife or a gun.

In the shooting gallery,if the background is of the castle, you can see fireworks by shooting the moon to turn down the lights then shooting the castle that will start the show of fireworks.You can only do this once per round and it adds 300 points to your score.

If you are low on health spray and herbs when at the lake take aim at the fish and fire away. When you hit a fish it floats. Jump in the boat and ride over the fish and take it. Depending on the size of the fish it will give you health.

When you encounter the 3rd form of Las Plagas, if you stand still then they cannot harm you at all. Eventually they will die by themselves.

At various points throughout the game, you will come across different animals such as crows and fish. These animals can be shot and will reveal different items or amounts of money to obtain.

During the 1st part of the game, after the village you will come a farm with many cows. If you knife a cow enough times it will kick you to very very low health, but it will not kill you.

When fighting Saddler, knock him down and stand near his eyeball head so that the "Knife" action appears. Shoot him instead and then start tapping "A" to do the action attack as well.