A heavily armed enemy transporter ship is carrying Disilicate energy crystals for the approaching Phalon mothership.
Once these have been installed in the deadly Phalon war machine they will turn it into the most powerful destructive force in the Universe. Capable of destroying entire solar systems in minutes, it must be stopped.
You have been chosen to represent the Federation forces. The new Thunderfox - an ultra-sleek and incredibly manoeuvrable space fighter - has been given to you in a last ditch attempt to destroy this evil threat to mankind.
All you have to do is locate the crystals and destroy them to stop the war machine from being finished. They are situated inside the transporter and are guarded by the crystal guardian: Obvious if you think about it.
Your way into the transporter is restricted by two anti-gravity stabilisers located at the far right of the ship. You must bomb each five times before it is destroyed - not an easy task even for an avid games player.
It is very easy to run out of bombs while you're trying to knock out the stabilisers so an option to reload is built into the game. When you have used all your bombs, fly to the far left hand of the transporter and land on your mothership where your supply will be refurbished.
When you have destroyed both stabilisers, fly to the left of the transporter and land on the pad. You will then be transported to the bowels of the ship and enter the thermonuclear laser room.
If you come into contact with any of the lasers or the walls you will be instantly disintegrated.
Remember to watch the level indicator at the top of the screen. The intense radiation generated by the lasers will destroy your Thunderfox if you take too long getting through. Once you manage to get past the lasers you enter the energy crystal room where the guardian is waiting for you.
The Discilicate crystal is located in its head and you must shoot it ten times to blow it up. This is hindered by the mobile wall that moves up and down in front.
The playfield uses a split screen and in the bottom quarter is the long range scanner - which indicates how close the Phalon war machine is to the transporter.
This distance is constantly closing, so time is of the essence - don't mess around shooting enemy vessels that you can just ignore. Also at the bottom of the screen is a status line showing your score, lives remaining, weapon in use and the current level.
The main action takes place at the top of the screen. An extra ship is awarded for every 5,000 points scored, and your total score is calculated depending on a number of factors, such as destroying the guardian head and blowing up ground installations.
The game is joystick controlled, allowing you four directions of movement - up, down, left and right. If you are travelling flat out when you push forward or backwards you will accelerate or decelerate relative to the movement.
However, when your craft is moving at its slowest speed, when you pull in the opposite direction it will flip over and reverse its travel.
The fire button is used to activate the on-board lasers but it also switches from lasers and bombs when you hold it down and move in the opposite direction.
The graphics are nice with lovely scrolling. The sound effects are well implemented and there is a catchy main tune.
When your fighter launches from its hangar you get a superb side-on view of it - an original feature. Also, when your craft is hit by enemy fire it doesn't explode straight away. It plummets to the surface of the transporter - another nice idea.
The game is quite difficult to get to grips with, but after the initial hiccups it got me hooked. I would recommend Thunderfox to lovers of shoot-'em-ups.