aRC-TeK is a four-page TTRPG that uses the RCTK system for subaqua Arctic dungeon-delves. 

https://porcupinepublishing.itch.io/arc-tek 

The Precursor Sites are abyssal dungeons were dug into the ocean floor millennia ago, hidden beneath the icy, inky waters of the Arctic. The aRC-TeK organization sends subaqua teams like yours to retrieve alien tech and extraterrestrial materials from the Precursor Sites. Treasure items are rated in GP (generative potential) upon return to the substation and you are rewarded accordingly. 

It is not simply exploration. The aliens are gone but their servitors remain. Biological, mechanical, biomechanical. These constructs and creatures are studied and recorded in an aRC-TeK recognition guide referred to by crews as the Monster Manual. 

When you encounter Precursor servitors or rival crews, it becomes a game of stealth, detection and submarine warfare. 

You return to the surface station for downtime, during which you can fix and upgrade your subs, interact with other sub crews and station personnel, and build connections within and outside the PC team.