The Signal From Tölva [instant Steam key]

Released on 2017-04-10

Included on PCGamers' 2021 list of best FPS games: https://www.pcgamer.com/best-fps-games/

The Signal From Tölva is a single-player, first-person, combat and exploration game. This deliberately slow-paced and engaging FPS has shades of Stalker with a gorgeous sci-fi open world that's based on concept illustrations by former Rockstar artist Ian McQue. You hijack a surveyor drone, investigating the signal in the title, and fend off other robot factions as you explore the planet's surface.

Later in the game you get to command other surveyors, too, who can help you in combat. The unusual and memorable setting, combined with great sounding and feeling guns, makes this one of the more notable recent cult hits on Steam.