I have been receiving ZX Computing for about a year now, but am amazed to have never seen Silversoft's Orbiter reviewed. So, now I have a chance to tell the readers what a fantastic program it is!
It's nearly exactly like the arcade game Defender. You have to trave in your ship across the hilly landscape blasting any green aliens you come across. The aim of the game is to retain 10 blue objects which lie along the bottom of the screen amongst the landscape. You are given these at the start of each game and the green aliens try to attack themselves to these and move towards the top of the screen. The aim is to first blast the alien and then catch the falling blue object before it hits the ground and is destroyed. Points are given for catching it and returning it to the ground safely. However, if you don't stop the alien and it reaches the top of the screen, it changes into a purple-coloured alien. Its movement is much more erractic and they move faster making them difficult to hit.
The layout of the keys is cleverly done and they include up, down, thrust, fire, change direction, hyperspace and smart bombs. If used, the smart bombs destroy everything on the screen with an impressive flash.
Besides the resident aliens there are also, blue and purple squares which move diagonally across the screen laying mines as well as innocuous-looking yellow saucers which never move except when they are hit, when a hoard of smaller red saucers are unleashed.
The entire activities of all the aliens are shown on a long-range scanner at the top of the screen.
As you progress through one attack-wave after another, you are awarded extra ships and smart bombs. I've found that after 200,000 points, the computer becomes very generous with these.
One drawback with Orbiter is that you are only shown a maximum of three ships and three smart bombs on the screen, so if you have more than three it is impossible to tell how many more. One time, out of curiosity, I let my ships be destroyed and found that I had 18 ships apart from those three shown (this was at about 350,000 points).
The danger in this addictive game is that, if the green aliens swipe all your blue objects there is a flash, the landscape disappears and from then on all the aliens are automatically changed into men purple ones. The secret to survival is not to, at any cost, let this happen, because if it does you're in trouble. So when down to the last blue object, instead of setting it down on the ground after taking it from the alien, hold onto it - for as long as you do, no aliens can pick it up. Then you try to reach attack wave 10, where you are given five free blue objects after every attack wave.
At £5.95, I think Orbiter is well worth the money.