To unlock a cheat you must get a gold medal on the indicated level:

Crazy Deaths: Lucky's Bar level
Gun Splitters: Crack House
Unlimited Ammo: Pier 74 Revisited
Invulnerability: All levels
No Reloads: Stark Towers
One Shot Kills: Ryker's Island
Unlimited Slaughter: Takagi Building

To achieve a high score, grab a human shield and use him. Shoot some enemies and try not to get hit. The longer you go without getting hit, the higher your points get. However, if you somehow get hit your points are rounded up and you must start again with not getting hit.

When you reach the funeral home level, do not jump up and just shoot everyone. If you get out of the casket and do a quick kill on everyone in the room, you will earn a lot more points. You should keep one of them alive to use as a human shield. None of them have guns in that room.

When in KingPin's office, throw grenades at him. Do not try to shoot him unless you aim for the head; bullets do not hurt him. Just keep throwing grenades until he dies.

To defeat Bushwacker you must do two things. First, aim for his head and fire. Eventually, his glasses will fall off. Once, his glasses are off it is a free for all as long as you have some flashbangs. If you do not have flashbangs, then just kill some henchmen and they will drop some. Begin launching flashbangs near Bushwacker and he will get disoriented. When he starts moving around like he is drunk, start shooting him. He will begin to fire his weapon, but most of the time he is inaccurate. He eventually will die after enough damage is taken.

Jigsaw is quite possibly the easiest fight in the game (if played smart). First, take out Jigsaw's jet pack. Simply walk over to a cargo crate. Make sure that you can see Jigsaw, but he cannot see or hit you. If you wait, Jigsaw will come to you. When he gets close enough, run under him. Then, just shoot his backpack and stay under Jigsaw. After a little cat and mouse, an intermission sequence will play. Jigsaw is now on foot. Jigsaw's way of defense are ten fast blasts and a large plasma ball. You will need to run in between boxes to throw him off your path. Run around until you see a guard, then finish him quick. The guard will drop a RAM explosive. These are used by walking up to a wall and pressing Secondary Fire once (while RAM is selected). The charge is now armed and ready for detonation. Get Jigsaw's attention by letting him see you. He will run after you. When he gets near the RAM, press your Secondary Fire again (maintain safe distance) and an explosion will blow off a piece of Jigsaw's armor. Repeat this procedure until Jigsaw falls to your punishment.

When you are fighting Jigsaw, get under him when he is in the air and shoot his jetpack. When he turns around, get behind him and shoot him again. Plant mines on the ground and detonate them when he walks by to finish him.

When you reach this part of the level, you may be compelled to take the sniper rifle to your left. You can if desired, but it is not required. If you want to get out quick, run to the middle rock near the edge (where the chopper is flying). You will find an anti-tank launcher (rocket launcher) and what may be an unlimited ammo cache. Try to aim for the man with the rocket launcher in the chopper (usually on the right). After you hit him, keep firing missiles at the chopper. Make sure that you strafe (or at least keep moving), as there are snipers in almost all directions around you.

When you get off of the gondola, take a right into the shed. Do not go to the launch pad yet. Get the ammunition for the sniper rifle. Leave the shed and make a right to the steps to the missile launch pad. Walk up the steps and the Russian will say "We have to stop meeting like this, Big Boy!". He will stay on the catwalk above, throwing flaming barrels at you. Shooting him is useless. Watch the Russian through your more precise aiming (it is easier this way). When he lifts a barrel, he will walk a little way, lift it above his head, and it will catch fire. Shoot the barrel while it is on fire before he throws it at you. It will explode in his face. After two or three explosions, guards will begin to appear from the right and left sides of the map. Take them out if they give you a problem, however try to focus on the Russian. After the Russian's life gets half-way down, an intermission sequence featuring him catching ablaze will play. He will then jump down and chase after you. Get him to chase you into the piles of barrels scattered in the corners of the map. There is one barrel in each pile that will light (usually the brightest one). Get the Russian to walk into the barrel and it will ignite. Then, shoot the barrel to blow it up on the Russian. Be careful not to get too close or you will sustain damage. After about four to five explosions, he will be defeated. Note: If the Russian runs into a guard, the guard will also catch fire.

When the chopper first starts shooting at you Iron Man flies in to give you a quick heads up. He then flies around the corner of the building.

When you grab enemies with skulls over their heads, you can get information from them. In order to do special kills, you must walk over to a purple skull shining out of the ground with the enemy. To do this, you must grab him and take him over to the purple skull. Then, use his own method.

Create a new profile called "V Pirate" and it will unlock EVERYTHING in the game except for upgrades.