Few games on this hallowed list of C64 classics can claim to have aged as well as Nebulus; John Phillips quirky little platformer-with-a-twist.
In this instance, 'twist' is the right word, as the basic idea was to guide little squat alien called Pogo from the bottom of a cylindrical tower to the top, via lifts, stairs, and doors, avoiding various hazards along the way. Presented in 2D, the game featured some of the best visual trickery ever seen on the humble C64, proving - if further proof were needed - that the machine was highly capable when pushed by wily British programmers.
Aside from the highly detailed sprites and eye-catching parallax effects, Phillips came up with a wonderfully original pseudo 3D technique which rotated the tower clockwise or anticlockwise, relative to your left or right movements. As you moved, Pogo stayed in the centre of the screen, but the impression of movement was brilliantly handled. A similar technique can actually be seen in one of Super Mario Galaxy's levels.
Armed with a rather weedy pop gun, you could dispense certain enemies and freeze others in their tracks, allowing you to slip past them, nip into a nearby door, appear out the opposite side and jump on a lift with impeccable timing.
Although you weren't killed for bumping into your enemies, it would often knock Pogo down several rungs of the tower, leaving you with work to do in order to reach the exit within the time limit. If you got knocked into the water, though, it was curtains for Pogo who was clearly unable to swim.
In between towers, an ultimately pointless but pretty bonus section gave you a chance to earn extra points by shooting fish. Most of the time, though, you'd end up gawping at the awesome parallax effects. In 1987 it was all about parallax.
As for the multitude of ports on other platforms...somehow they just didn't have the soul of the original. To see it at its best, check this version out.