Nebulus is a vertically scrolling platform game created by John M. Phillips and published by Hewson Consultants in the late 1980s for home computer systems. International releases and ports were known by various other names: Castelian, , Subline, and Tower Toppler.
| award1Pub = Crash
| award1 = Crash Smash
| award2Pub = Your Sinclair
| award2 = Megagame
| award3Pub = Amstrad Action
| award3 = Mastergame
Compute! stated that the Commodore 64 version of Tower Toppler had "good arcade action, with well-executed graphics".
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