Your mission is to rescue pilots who've been shot down behind enemy lines. The fractal terrain is mountainous, with laser turrets on the mountain tops and kamikaze flying saucers. While blasting the aliens you must use radar to scan for downed pilots, then land nearby to pick them up. If you're close enough the pilot runs up and bangs on the door to be let in. Simple...
But wait, doesn't that pilot running to you have a green head? It's a Jaggi alien and he's bashing through the windscreen! Quick, switch the shields back on and fry him! Phew! Lucky you didn't open the door, eh? A Jaggi in the ship is a one-way trip to disaster!
In fact, Rescue On Fractalus has stood the test of time well. The illusion of negotiating valleys and canyons is done well and even now the fractal effect is impressive. The sound effects are a little simple nowadays although the footsteps of the pilots and their subsequent banging on the ship door are excellent. Sadly, higher levels change very little other than throw more aliens at the pilot (ultimately lessening the elements of surprise and the unknown). Such gripes are minor however, when you consider the tension, addictiveness and sheer fun of it all. "Buy this piece of software history or die," as the Jaggis might say!