One of the key factors which make this an all time classic games must the way in which it is infuriating
difficult without seeming unfair. Just trying to stay alive was hard enough without the combined
difficulty of trying to prevent landers turning into mutants. They did this by picking up the humans
wandering the landscape carrying them to the top of the screen and fusing into new deadlier mutant ships.
Around 60,000 of the original arcade units were sold and are still available now for around £2000 if
you can find one.