This game is a version of the arcade game 'Scramble' and is priced at (what I thought was quite a lot of money) £5.50.
The tape loaded easily and you are presented with a score table and a demonstration game so that you can get some idea of the action before you begin. If key 1 or 2 are pressed, you get a one- or two-player option respectively.
In the game, which is somewhat similar to the arcade game except for the final stage, you get to fly your ship through various caverns watching out as you go for the enemy missiles and flying 'nasties'. If you hit the fuel dumps, the ship is re-fuelled. The graphics are good all round and the keyboard layout is well laid out. Not much luck is involved in this game!
My only complaint is that the bomb and firing keys are not auto-repeat - but this could be sour grapes because I get shot so often!
The game is hard to master and I have still yet to destroy one of the large fuel dumps in the last stage. The instructions supplied with the game are helpful and easy to follow, and the game itself is incredibly user-friendly.
As for the price of the game, I think it is worth every penny, and if you're as hooked on 'Scramble'-type games as I am and have a 16K ZX81 (and don't mind waiting six minutes for it to load!) I would suggest you waste no time in buying it.