Gun and Display Cheats
Give yourself unlimited ammunition with the code "ammo." Turn the gun mode display on and off by entering "gun" and toggle the game's heads-up display on and off with the cheat "hud."
Super Powers
Kill bugs without the fear of dying by entering the cheat "god." This will make your character invincible. You won't even have to fire at the big bugs when you use the cheat "evileye." Your enemies will die when you target them with your weapons.
Faster Action
Change the quickness of the action with the cheat "speed #." In place of the "#," enter any number you wish. The higher the number, the higher the game speed.
Super Cheat
Use the cheat "banzai" to give yourself plenty of powers. You'll be invincible and able to kill bugs by targeting them. You'll also make the speed of the game faster with this code.
Beating the Bugs
Defeat both the Royal Guard bug and the X-Bug by targeting their red eyes first. Once you shoot out the eyes, the nerve stems of both foes will be revealed. Take out this stem to kill the Royal Guard. The X-Bug takes a bit more work. Shoot the nerve stem and this enemy will rear up, exposing its soft yellow underbelly. Quickly fire at this to damage the X-Bug before it settles back down. Repeat this process to defeat the X-Bug.
Using the Missile Launcher
The missile launcher, also called the portable nuclear device, will wreak havoc on many enemies in the game, including tanker, plasma and rhino bugs. It does not affect the X-Bug or Royal Guard. Be careful when using the missile launcher -- don't aim too close to yourself, as an explosion near you will kill your character.