Shoot 'em ups
There weren't many PC shoot 'em ups that deserves to be mentioned, back in the day. Let's do a memory exercise: try to remember a few titles. Did you remember at least five good DOS shoot 'em ups? I tried and I remember only a few: Tyrian, Raiden, Xenon 2, Raptor.
Anyway, here are some lesser known shoot 'em ups published in the 90s for PC.