Cyber Police ESWAT is a 1989 scrolling shooter arcade game developed and published by Sega. In 1990, Sega released a Mega Drive/Genesis version known in North America as ESWAT: City Under Siege. It was ported to the Amiga, Atari ST, Amstrad CPC, ZX Spectrum, Commodore 64 and Sega Master System. 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.