Nebulus is a video game created by John M. Phillips and published by Hewson Consultants in the late 1980s for various home computer systems. International releases and ports were known by various other names, including Castelian, Kyorochan Land (キョロちゃんランド, Kyorochan Rando), Subline and Tower Toppler.
The game's original 8-bit release received some critical acclaim, in particular the Commodore 64 release, which garnered a Gold Medal award from UK magazine Zzap!64.
Nebulus was followed by a lesser-known sequel, Nebulus 2, on the Amiga in the 1990s. An Atari ST version was also in development but was cancelled.