Immediately recognisable as a version of the popular Defender arcade game, Orbiter incorporates many of the features of the original, such as Landers, Mutants, and the small scale display of the overall battle area.

Since these features are not mentioned in the brief instructions, it was only after consultation with a confirmed Defender fan that the full scope of the game was understood.

It then emerged as quite entertaining, if slightly frustrating game, notably in the fact that the score message kept chaning colour, and in some colours was quite unreadable.

The Defender fan remarked that it was difficult, if not impossible, to position the defending ship so that attacks from the rear could be detected in time to take evasive action, but that could be seen as part of the fun.

The program loaded without difficulty, though the instruction to CLEAR 25102 before loading was a little surprising, not being needed with other machine code programs. Seven control functions were available, each controllable by a separate group of keys in the keyboard matrix.

Basically a good game, which would nevertheless benefit from slight revisions and an adequate explanation.

D.T.