RaidenX

Enter or Space - Confirm option menus and pause game during play.
Z key - Fire your guns and missiles.
X key - Release a bomb.
Arrow Keys - Steer your fighter-jet.

One of the coolest things about RaidenX is the weapon changing system. This works through the use of Gun Powercubes. These are square powerups that cycle colours through red, blue and purple, changing colour every 4 seconds.

Picking up a powercube of the same colour as your current gun raises the power level of your gun. Picking up a cube of the different colour changes your gun to the one you picked up, keeping it at the same power level.

The red powercube represents the Vulcan Gun, a standard spread of yellow shot. Powerups increase the spread and intensity of the shot, thereby increasing screen coverage. Goes well with nuclear or homing missiles.

Strengths: Mini-bosses
Weaknesses: Bombers

The blue powercube represents the Laser Beam, a beam of energy that fires straight forwads. Goes well with homing missiles.

Strengths: Bosses, mini-bosses, bombers
Weaknesses: 1HP enemies, fast moving jets, asteroids

The purple powercube represents the Plasma Ray, an electromagnetic whip that can lock onto multiple enemies at once. Goes well with nuclear missiles.

Strengths: Asteroids, fast moving jets, tanks
Weaknesses: Bosses, mini-bosses, bombers

5 Bombs
On the title screen, select "New Game" whenever the background animation is flashing white. If you get the timing right, you'll start with 5 bombs instead of 3!

For a better success rate, play at 300x350 resolution to reduce lagging.

Hidden 1UP
In stage 3, just before you reach the open harbour, you'll see a blue box marked with a "?". Don't shoot at it (if you have homing missiles or a wide-spread gun, let go of the FIRE key). Try not to die either, or the debris of your ship may hit the box.

Wait until a nearby tank comes out of its base and runs over the box to break it. Out comes your free 1UP!

Invisibility Mode
During the takeoff sequence after stage 5, press CTRL. A textbox at the bottom-right corner will pop out. Type in "go0gleypower" and after the animation (stage 6), you'll remain invisible for 20-30 seconds. Survival guaranteed!

You'll return to normal at around the time you see the ruby (which gives you a 1UP).