

Laser Squad (1988) was among my favourites growing up, they are the precursor to UFO/XCOM (the original from 1993).
I will add Rebelstar (1986) on the ZX Spectrum, the granddaddy of them all. Technically there was Rebelstar Raiders beforehand but that version didn’t have a computer opponent. I feel that Rebelstar is where the design elements that defined the later games came together.
Sorry to nitpick but there were several Batman games before that. The first one that I know of was Batman (1986), an isometric exploration game on 8-bit micros. It’s a very good game for its time and the engine later evolved into Head Over Heels (1987) which uses a different theme.