Successfully complete the game to unlock bounty hunter mode and hard mode.
Play through the game in bounty hunter mode to unlock various cheats, including "Invincibility", "Infinite Deadeye", "Golden Gun" (one hit kills), "Bite the Bullet", "Sad Stars", "No HUD", "No Distortion", "Show Player Position", "Show AI Info", and "Big Money".
Man with no name
When starting a new game, instead of entering a name use the spacebar right to make a blank entry. When you enter this, it starts a character named "Rstar". In some of the stores some items show up as already sold to you.
Beat Mr. Black
Kill the other guys, strafe in a circle around him and roll as much as you can when he opens fire with the coffin gun, as he flips over it (or maybe it's right after he flips over it) start firing at him with everything you have. He'll stagger and take serious damage from your bullets as he does. When he regains his balance stop shooting, start circling him again and reload. Use the double pistols and don't bother shooting any other time than what is listed. He won't take very much damage if you do.
Defeating The Exploding Dynamite Boss
On the level with the exploding dynamite Boss, sneak around and hide so that he does not see you. Note: Bongo music will play when he is on your tail. Then, shoot him with the rifle in the back. This surprises him (the game will say "You surprised him!"). Then, power on through with as many shots as possible to get his life down. Repeat the hiding routine, then sneak shot again. Do npt use combos, as they do not really effect him much. Just power on through with single shots; because the first one stuns and the successive ones hurt him. Also, when he is on your tail and is going to blow you up, do a sidestep or one of those rolls to get out of the way. The area with the low cement walls works well if you duck down.
Store items already sold
When starting a new game, instead of entering a name use the spacebar right to make a blank entry. When you enter this, it starts a character named 'Rstar'. In some of the stores some items show up as already sold to you.