Alien type multi-digit hands are needed to keep up with the key pressing action demanded in this game. Nine keys are used to defend your space base from alien attack. You lose power if they damage your force field or if you bring your laser cannon or neutron gun into action. Help is at hand though in the shape of a repair craft, which can restore the force field and hence energy levels.

If more than one alien crashes into your generators you're finished. There are six types of alien to destroy, each with a different points score. There are five difficulty levels and the five highest scores are automatically recorded. Standard keys are set for playing, but these can be altered by selecting the appropriate menu option. Error checking is limited since the program is tightly-squeezed into the TI memory, so take care in resetting keys or by pressing enter as default you could end up with a stuck game.

Only one key operates at a time, so the game has an infuriatingly high frustration quotient. In this respect the game is cleverly fashioned to give you so many things to think about that you don't worry about the typically jerky movement of the slow TI basic. All the while, a lower screen display monitors your defence levels and score.

The packaging and instructions are to Intrigue's usual high standard. Slow TI basic or not, this is an altogether professional effort, giving very good value for money.