Games like Threshold Sector

"P.A.M.E.L.A. is a single-player, open-world horror game set in the decaying utopian city of Eden. As a Sleeper, scavenge for resources, build and upgrade equipment, and navigate relationships with various factions to survive. Experience a dense atmosphere, stunning graphics, and a good plot, but be prepared for numerous bugs, grinding, and subpar optimization."

"Ripout is a Co-Op horror shooter with excellent graphics and mechanics, allowing 2 players to fight through mutant-infested spaceships, collect loot, and customize characters in search of humanity's last bastion. Engage in high variety of reconfigurable monster battles, with a derelict ship exploration in single-player or small teams. The game's phenomenal atmosphere and grinding opportunities ensure hours of entertainment."

No More Room in Hell 2 is a tense co-op survival horror where up to eight players must navigate zombie-infested zones using strategy and teamwork. With permadeath and dynamic, ever-changing environments, every decision carries weight against relentless hordes. Survive, scavenge, and complete missions while battling infection and deadly threats lurking in the dark.

Unexplored 2: The Wayfarer's Legacy is a genre-bending RPG with a table-top feel, offering a procedurally generated open-world and strategic exploration challenges. The game features a rich narrative, award-winning soundtrack, and beautiful art style, with a learning curve that offers systemic depth and rewarding gameplay. It also includes a wide range of difficulty modifiers, allowing you to customize your experience.

"Unsafe" is a horror survival game with action elements, playable in single-player or with up to 4 players in co-op mode. You wake up from cryostasis in a desolate space station, the "Black Monolith," with no memory of what went wrong. Work together to bypass security systems, gather data, and stay alive while facing dangers. Utilize tools and proximity comms through your microphone for survival. A mega update for "Black Monolith" and a second map are in development.

"Frozen State" is a survival game set in a man-made ice age, where you must repair your transport and survive in a vast, randomly generated world filled with humans, military groups, and alien hybrids. With a deep crafting system, diverse enemies, and the goal of repairing your transport while uncovering the city's story, the game offers rogue-like and normal modes, and features three main characters. Dynamic weather conditions and a large open world complete the experience.

Into the Dead: Our Darkest Days is a side-scrolling survival game where you guide a group of zombie apocalypse survivors through a devastated city. Scavenge resources, craft weapons, and manage your group's needs while upgrading shelters to protect against relentless undead threats. Your goal is to get everyone to safety amid the chaos of an unstoppable outbreak.

"CONVRGENCE is a single-player horror shooter with stellar gameplay and outstanding graphics, resembling an extraction shooter like Escape from Tarkov set in a procedurally generated Chernokamensk exclusion zone. At night, eerie monsters and your own fear transform the gameplay, and wise planning is essential to survive, scavenge, and extract. Despite some bugs, CONVRGENCE boasts a phenomenal atmosphere."

"The Last Stand: Aftermath" is a survival-action role-playing game set in a post-apocalyptic world overrun by zombies. The player must scavenge for resources, craft items, and navigate through a dangerous landscape while managing their health and stamina. With a focus on melee combat and strategic decision-making, the game offers a challenging and immersive experience in a grim, post-apocalyptic setting.

"The Pit: Infinity" is a rogue-like, sci-fi shooter that pits players against hordes of alien creatures in a procedurally generated arena. With a wide range of weapons and abilities to unlock, each run offers a unique and challenging experience. The game also features a permadeath system, adding an extra layer of tension and strategy to the intense combat.