- Joystick: Use the joystick to direct Billy on the screen. Billy can move in eight directions throughout all of the visible screen. However, the game will continue to scroll the scene forward, except during boss fights and other particular instances.
- Fire Buttons: There are three fire buttons, arranged in a small semi circle. Pressing the highest button in the center will cause Billy to shoot straight forward, while pressing the buttons on either side will cause Billy to shoot at an angle to either side. Combinations of buttons also cause Billy to fire at different angles:
|Left + Center||Center||Center + Right|
|Holding the left and center buttons down directs Billy to fire his guns at "11 o'clock."||Pressing the center button alone causes Billy to fire straight ahead, or at "12 o'clock."||Holding the right and center buttons down directs Billy to fire his guns at "1 o'clock."|
|Left||Left + Right||Right|
|Pressing the left button alone causes Billy to fire his guns at "10 o'clock."||Pressing both the left and right buttons directs Billy to fire each gun in opposite directions.||Pressing the right button alone causes Billy to fire his guns at "2 o'clock."|
- Note that under no circumstances can Billy fire entirely to his right or left, nor can he fire his guns behind him.
- 1-2 Players: Press either button to begin a one or two player game.
Billy is the bounty hunter who has accepted the mission to remove the Wingates and related threats from the once-prosperous gold mining town that has become the target of bandits. Each leader has a price on their head, and Billy is prepared to take them all down, one at a time.
In the original arcade version, Billy has only one option for weapons: his trusty pair of hand pistols. Billy is quite skilled with them, and he can fire them at a variety of angles. Unfortunately, the one thing he can't do is fire directly to either of his sides or behind him. Billy has an unlimited amount of ammo for these hand pistols, so don't hesitate to fire as rapidly as possible. (In the NES version, Billy can also purchase additional weapons if he has enough money. However, these weapons have a limited amount of ammunition.)
Guns are quite lethal, and most enemies will fall to the ground after getting hit with just one shot; this includes Billy. Anytime he is hit by a bullet, an explosion, or by direct contact with an enemy, he loses one life. If all of his lives are lost, the game is over. On most machines, the default setting is to award Billy an extra life at 30,000 points, again at 100,000 points, and at every additional 100,000 points thereafter.
During Billy's adventure, he will come across barrels. If he shoots those barrels, he may find items inside. These items can be collected for power-ups or bonus points. Billy can carry up to five of each power-up. However, carrying more than one does not increase the effect of the power-up. In other words, if Billy collects three speed-up boots, he will not travel any faster than he does if he has one speed-up boot. If Billy dies, he loses one of each power-up collected, so having more in reserve is simply a guarantee that Billy will remain powered up when he returns to the game with his next life.