Eliminator is a 3D shoot 'em up for home computers published in 1988 by Hewson Consultants. Versions came out for Amiga, Amstrad CPC, Atari ST, Commodore 64 and ZX Spectrum. More information on Wikipedia.

A trainer offers one or more cheats like unlimited lives, invincibility, more ammo etc. Because this is done during runtime a trainer is not to be confused with a savegame editor.