Kickstarter: Underworld Ascendant

Paul Neurath, the founder of Looking Glass Studios, has assembled a team to make a modern sequel to the Ultima Underworld games. LGS was the pioneer of the immersive sim genre where immersion is first and foremost encouraged through a living breathing world that reacts to the player in logical and consistent ways. But their games (Thief, System Shock) also had an excellent horror atmosphere, letting you creep around haunted zombie-infested cathedrals and space stations crawling with hideous mutants.

Give it a look, if first person underground exploration sounds like something that may interest you: