Do it to them before they do it to you, as a crab-like tank or a high flying plane.
Imagine a world where everything is blue and seen from a bird's-eye view. Well, that is the planet Xenon. It is a hostile world, and the only means of survival is doing it to them before they do it to you.
You take the form of a craft; not any old craft, though, this one is special. It is a land and air craft, capable of switching from being a small, blue, crab-like tank which trundles along the ground firing at the enemy tanks, to become an aeroplane which flies above the tanks, dodging their bullets and blowing up the firing towers and the enemy aircraft below.
Having loaded the game, the menu offers you the choice of keyboard or joystick. What with metamorphisizing every few seconds, though, and firing as you move left, right up and down, I do not recommend using the keyboard. The joystick is more versatile and easier.
Until your energy diminishes, air play is fast and furious, but then your movement tends to slow down dramatically. Life as a tank progresses at a robotic snail's pace in comparison. This can often be an added bonus, however, as I frequently found myself flying far too fast into the face of adversity; I was killing the enemy but watching my own energy level diminish at an alarming rate while I should have been crawling steadily towards them firing at will. The game is very one-sided, because every weapon the enemy possesses can kill you, regardless of shape and form.
The object of the game is to dodge a fair minefield of firing objects while destroying everything in sight, armed only with your trusty craft. Confronted by this, my personal instinct was to turn around and go home, but planets were not saved by that sort of behaviour. You are helped slightly by having three lives and the opportunity to replenish energy, bullets and firing range by travelling over the relevant pod which appears intermittently.
It is not easy. Once everything on the first screen has been destroyed and you have managed to duck and dive, dodge and weave past all the missiles that the computer can throw at you, there is still one final obstacle to overcome before progressing to the second screen. This is a giant tank. It fires like crazy and its defence is impenetrable.
Yours, on the other hand, drops like a dead weight, because you have only the smallest of openings to hit him where he is vulnerable. Get past him and you are doing well. The next screen is much like the first with yet another huge tank at the end. The game continues like this as you try to increase your score and wipe out all evil from the planet Xenon.
My only two criticisms: every time you die - and this is frequently - you have to return to the beginning, and the music is on the tinny side, but the sound effects, which are very realistic, compensate for it. It may all sound a bit too difficult but do not be deterred; it is an enjoyable game and one that comes with practice.