The procedure is simple: all you have to do is climb the tower, triggering it to self-destruct, after which you can swim to the next one. In order to reach the top of each tower, though, you have to follow a mazy series of spiral steps built around the outside of the tower. Which is where the game's amazing rotational 3D scrolling comes in. This great feat of programming (for its time, of course) allows you to travel round and up the tower, entering and exiting various doors to emerge at different parts of the tower smoothly without ever going to the edge of the screen. Instead, the tower winds like a screw in your monitor, and the 3D effect is very convincing.

The further up you go, the more devilish puzzles you'll need to solve. And speed is of the essence too, as you have only three lives, and the on-screen counter counts down incessantly. The suspense is high, as you can't tell what you'll encounter round the next spiral turn. In terms of enemies, flashing blocks and bouncing balls can be zapped to add on points, but silver spheres can only be momentarily stunned. The snow crystals are immortal are very annoying – all you can do is run away from them.

Overall, Nebulus has little to fault it, barring a lack of colour in the graphics and lack of save mode – clambering back to the top when you have tumbled from a peak can be tiresome. Otherwise, Nebulus is a great classic that truly stands the test of time. Two thumbs up!

Rob's review from when the game was at CW#3: "Classic platform/puzzle game by Hewson in which you have to reach the top of various tricky towers before the timer runs out. I remember this one very well on the C64. The pseudo 3D graphics were amazing for its time, but the game also has original addicting gameplay which makes it an all-time classic in my opinion. Go figure it out for yourself, the IBM-PC conversion isn't bad. Colors look a little strange due to the EGA palette, but the game plays as well as the original 8-bit versions."