Each of these cassettes contains two fast machine code games. They are all impressive considering the exceptionally small memory available on the unexpanded machine.

Unlike many 1K programs, all these cassettes load and run directly on 16K machines and there is no need to reset RAM-top. Apparently this is due to a software feature which converts the ZX81 display file into a true memory-mapped VDU releasing extra memory as a consequence. Selec Software have certainly done well to get these very good games into 1K of RAM.

In ZX Panic, the screen displays a field randomly and liberally supplied with electricity pylons. A killer virus has been released and you must spray as much of the field as possible with a poison to kill it. Once you start, you are unable to stop and must avoid hitting the pylons, your own poisonous cloud or the edges of the field. Your score is displayed on screen.

ZX Squash is a simulation of squash for two players. Each player has a bat (or racquet) which is moved along the bottom of the squash court, and each in turn tries to hit the ball as it bounces off the court walls. The first player to reach fifteen points wins. I would have liked the bats to move a little faster; as it is, the ball is often impossible to reach.

Maze Guzzler is a 'Pacman'-type game, with all the usual facilities found on the 16K versions available. Because of the restricted memory, the maze is rather small, and the action is perhaps rather slow, but does increase in speed as the game progresses. There are two 'intelligent' monsters which must be dodged, and dots to consume. There is even an energy pill which will allow you to chase the monsters for an addition 20 points - for a short while. On-screen scoring is provided. Quite amazing for a 1K game.

Super Breakout on the B side is Selec's version of this popular game, of which there are already a number of 1K versions. The action is fast and responsive, although the display is not full screen.

A very good 1K version of Invaders is on the A side. The action is as good as many 16K versions although again the limited memory has dictated a display which is less than full screen in size.

Time Bomb on the other side of this cassette is a frenetic game in which you have to reset bombs which appear randomly on the screen. The game ends when a bomb counts down to zero and explodes. As more and more bombs appear as the game progresses, it is only a matter of time before it becomes impossible to rush round and reset them all.

If you are in the market for 1K games, all these cassettes are to a good standard and are worth considering as a reasonably good buy. It is certainly surprising what can be achieved for the 1K ZX81 with a little ingenuity.