Terra Force is from the recently launched range of budget software from British Telecom. This invaders derivative has attractive 'baroque' style graphics which class its appearance higher than the norm.
Your objective is to defend the earth and the moon from Ygothulu, a sort of green crab, hovering at the top of the screen. You use your laser base to shoot the chains of green eggs that cascade down the screen. Eventually, the eggs spawn beautiful, deadly, winged insects which rain bombs upon you. Five direct hits annihilate Ygothulu, I managed to achieve this once or twice. I could not manage to reach the third level, so I cannot report on what additional nasties are lying in wait.
With smooth, nicely-designed graphics, sound effects, selectable difficulty factor, high score feature and Kempston joystick compatibility, there is nothing to suggest that this game can be obtained for a modest £2.50. Although the plot is a little derivative, it's worth emptying the loose change out of your pockets for this one.