Unknown Depths is a co-op horror adventure game for PC that blends action and indie sensibilities into a tense descent through an enormous, procedurally generated shaft. Players work together as a team of divers to climb down as far as possible while evading a creature that tracks movement through scent trails left in the open air. The experience emphasizes careful navigation, resource management, and coordination in a setting where light provides the only real safety and one mistake can end a run instantly.
Gameplay
The core loop revolves around descending a vast vertical shaft filled with ledges, drops, and hazards. Each diver carries a grappling hook attached to roughly 25 metres of rope, which serves as the primary tool for movement. Players can catch ledges to swing across gaps, rappel down sheer walls, or haul themselves upward when needed. The hook also allows teammates to pull one another to safety or link ropes for shared traversal. Physics play a major role, as falls cause damage, stamina depletes during prolonged effort, and poorly timed swings into rock can prove fatal before the creature even appears.
Movement leaves a visible trail of glowing dust that lingers after a quiet period. The creature senses this scent and grows from the walls when it detects a trail, announced by a rising clicking rattle and shuddering rock. Once active, it inhales across the shaft to follow the scent directly. Lanterns, glowing fungus, crystals, and shrines create safe zones where no scent remains, forcing players to dash between pools of light while managing the trails created by each dash. The shaft itself changes with every attempt due to procedural generation, making each descent unique and tying progress to depth reached as the score.
Game Modes
Unknown Depths supports online co-op for one to four players, with the option to play solo if desired. Three difficulty settings shape the challenge. Easy and Normal modes feature a single creature, while Nightmare introduces multiple worms that hunt simultaneously. Runs continue until the entire team is eliminated, at which point the shaft resets for a fresh attempt. Dead players observe the living teammates and can contribute by kindling shrines that revive the full group when activated. This structure encourages repeated descents focused on deeper progress and better coordination rather than traditional levels or campaigns.
Visual Style and Atmosphere
The game adopts PS1-style visuals with wobbling vertices, dithered colour palettes, and thick fog that enhances the sense of scale and unease in the open shaft. These choices reinforce the horror elements without relying on modern high-fidelity graphics, keeping attention on movement, sound cues, and the constant threat of the creature emerging from the walls. The audio design highlights the creature through distinct rattling and breathing sounds that players must listen for during quiet moments between dashes.
Is It Worth Playing?
Unknown Depths suits players who enjoy co-op horror experiences built around precise movement mechanics and procedural variety rather than combat or story-driven progression. The combination of grappling hook physics, scent-based pursuit, and light-based safe zones creates a distinctive loop that rewards teamwork and quick decision-making across multiple runs. Those drawn to indie action-adventure titles with high replayability through changing environments and escalating difficulty will find the core systems engaging, particularly in groups that communicate well during descents. The instant-death consequences and team revival mechanics add tension without requiring external progression systems, making it a focused choice for sessions centered on survival and depth achievement.