Ikari Warriors is a vertically scrolling, run & gun shoot 'em up arcade game developed by SNK, published in North America and Europe by Tradewest, and released in 1986. Versions came out for Apple II, Amiga, Atari 2600, Atari 7800, Atari ST, Acorn Electron, Amstrad CPC, BBC Micro, Commodore 64, NES, MSX2, IBM PC, 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.