^gary graham appears in the weirdest stuff. i like it. not really for the story, but the stop-motion robots are cool. and some of godzillas enemies were giant robot creatures, so its close enough. i reckon G Gundam stole lots from that film.
giant robots fighting giant monsters has been done many times. just because a western film hasn't depicted it before doesn't make it original and mean you get to discount them purely for being japanese.