The following codes are valid for the Japanese version of the game and must be done in a sliding motion. No codes exist for the North American version.
Press Left, Down, Down/Left, Left, Start at the player selection screen. A hum will confirm correct code entry.
In the Japanese version, quickly press Down, Left, Down, Left, Start at the title screen to unlock the level select in single player mode. Quickly press Down, Down/Left, Left, Start at the title screen to unlock the level select in two player mode.
Press Up(2), Down(2), Left, Right, Left, Right, B, A, Start before the music starts at the beginning of the game
In the Japanese version, move the pointer above ‘Options’ at the main menu. Then, press Down, Right, Down, Right, Start at the title screen. The sound of life being lost will confirm correct code entry. Enter the options menu and ‘Player Lives 30’ will appear.
Press Right, Down, Down/Right, Right, Start at the player selection screen. A death scream will confirm correct code entry.
Briefly press L or R once, then hold the button in levels two or four. The screen will spin rapidly.
Hold L + R + Start and press Select during game play to return to the title screen.
Rapidly tap X while quickly pressing Down, Right on the title screen.
In the Japanese version, quickly press Down, Right, Down, Right, X at the title screen.
Note: This trick requires a controller with a auto-fire feature. Begin game play and assign X to have auto-fire. The weapon selection display on the top of the screen will rapidly change. Once two weapons are collected, both of them may be used simultaneously. Note: The flame-thrower is not effected by this trick.
Alternate ending sequence:
Successfully complete the game under the hard difficulty setting.
Hint: Extra lives:
There are two locations on level 1 where your character can remain motionless to collect extra points and lives. After starting level one, your character will find a futuristic car. Do not destroy it. Jump over it and use it as a shield against the attacks that originate from the left side of the screen. Keep firing towards the right side of the screen, instantly killing all opponents that appear from that direction to collect easy points and the occasional extra life.
Later in level one, your character will collect homing missiles. Take the missiles to the next higher platform, and out of the way of the ground activity. Use the missiles to destroy all enemies that come into range to accumulate more points and lives. Note: When playing under the highest difficulty setting, a maximum of twenty-nine lives may be accumulated.
Hint: Easy weapon change:
Press Start pause game play and press X to change weapons. You will notice that your weapons can change even while the game is paused.
Hint: Continue game play:
Play the game in two player mode. After losing all lives and having the other player still alive, press A or B (depending on which mode) to return to life.
Hint: Mini gun:
Select the Normal or Hard difficulty setting. Reach level 6 and the final Boss. Notice the different shapes moving around it. Shoot the one that resembles a spike and various guns and bombs will drop. Get under the Boss and wait until the gun marked with an ‘M’ appears. Collect it to get the mini gun.