Wrath of Earth.
FPS adventure-shooter that unlike Doom you actually have to use your brain to get through.
Played it back in my golden days on a half-broken DOS laptop.
Loved it 'cuz you had to inventory manage across multiple levels, adapt your combat strategy as enemies became radar invisible, and the environment was creepy.
Grab DOSBOX and give it a try.
NOTE: EMS MUST BE DISABLED
https://archive.org/details/wrath-of-earth