Nebulus (known as Tower Toppler in the US) is an action platformer developed and designed by John M Phillips. Initially it was created for the ZX Spectrum and Commodore 64. Later it was ported to Amiga, Atari ST, Amstrad CPC, Acorn 32-bit. There are also versions for the NES and Gameboy.
Cute graphics, brilliant gameplay and a revolutionary animation made a success. The main character sprite (a frog) is always in the center of the screen, while the environment (a tower) moves around it, giving the impression of a 3D rotation. The C64 version got a Gold Medal award from Zzap!64 magazine while the Amiga version was voted 14th best game of all time by Amiga Power. Nebulus also won the title of Best Original Game Of The Year at the Golden Joystick Awards. It's simply a game you have to try.