From the people who brought you Scope comes a novel way of using BBC graphics. Battle Planets is set in a long trench which stretches from the front of the screen and goes backwards in 3D. A very clever but little used feature of BBC Basic, known as colour swapping, is used to convey movement.
This makes the trench appear to come towards you very fast which gives the impression of you actually moving through the screen.
You may have seen this technique on the BBC programme, Making The Most Of The Micro. Remember that wonderful demo with two globes spinning in opposite directions?
Battle Planets is written entirely in Basic. You can even break into the program by pressing Escape, but this doesn't matter. The game is certainly not slow - in fact, if anything, it's too fast.
Your mission is to fly through the trench which is situated on these battle planets. The planets are actually giant spaceships which have invaded human civilisation as we know it (well, that's what it says on the cassette) and the trenches are weak spots.
As you travel along the trench, so you come closer to the very heart of the battle planet. Your ultimate mission is to detonate a plasma bolt at the centre, thus rendering it harmless.
You can move your craft up, down, left and right by using the keyboard. Pressing the Return key will fire the gun which serves to keep the robot fighters at bay.
You also have a force shield, although this doesn't last long and being cowardly will not give you a very long game.
All these keys are a bit tricky to keep a finger on at the same time, but you slowly get used to it.
If you're still alive after facing all that, then the commander of the robot fighters, hungry for some excitement after watching all the action, will join the fight. At this stage, there's not a lot you can do. He is indestructible, although a quick blast with a plasma bolt will paralyse him for a few moments. You only have three of these, however, and you must save one of them to destroy the heart of the planet. So life's pretty hard all round, really.
At the top of the screen is a display of your remaining energy. If this drops to zero, then you've had it. You are no longer. What I found infuriating is that you only get one life, which means that you have to start the game again by pressing the Space bar three times. You then have to wait while the game draws all the different colours which make up the trench so that the colour swapping will work.
Apart from that, though, the game is great. It's hard, but great. Graphics, as already mentioned, are good and sound is included too. For a game written in Basic, it is pretty sharp programming which, having seen their Scope games designer, I've come to expect from ISP.