The Cave’s story is based on a magical talking cave with a labyrinthine set of tunnels within it. Seven characters, drawn from across time and space, have come to the Cave, believing they can “learn something about themselves and who they might become”, as stated by Gilbert, while harboring a dark secret. In one example, a knight character, seeking a treasured amulet, encounters a princess who possesses the amulet in distress from a dragon; instead of coming to the princess’ rescue, he lures the dragon into eating her and recovering the amulet for himself when the dragon coughs it up.
At the start of the game, the player selects three of the seven characters, which they are then locked to for the remainder of the game; players can restart a new game to select a different trio of characters. The characters are based on stereotypical figures, such as a hillbilly, a pair of orphans (acting as one character), and a scientist.
As the player controls the trio to explore the Cave, they collect objects and interact with the environment in a manner similar to an adventure game. The exploration of the game is based on 2D platformer elements, though the game is presented with 3D graphics. Exploration is described as being “Metroidvania”-like, where more of the Cave’s tunnels and chambers become accessible as players collect objects in a manner similar to Metroid or Castlevania. The player will need to work with all three characters, switching between them typically to activate multiple parts of a puzzle; one example shown in early press demonstrations was to use one character to ring a bell to distract a dragon, a second character to repair a hot dog vending machine as to provide bait, and a third to operate a giant claw machine to pick up the dragon to clear their path. Each character has a unique ability to aid in maneuvering the cave tunnels, leaving some areas inaccessible if the appropriate characters aren’t chosen at the start; for example, the adventurer is able to swing herself across gaps with a rope, while the time traveler can phase shift a short distance, passing through closed gates. In addition, some areas of the Cave are accessible only to one of the specific characters; such as the knight finding a castle or the scientist discovering a laboratory; these areas represent the deep desires and dark aspects of a character that lured him or her to the Cave in the first place. While there are hazards that can kill a character, the character respawns shortly afterwards nearby, allowing the player to reattempt the move. Throughout the game will be iconographs for each of the three characters, which the player will need to get near to activate; these provide one of several still art images that reveal the character’s back-story.
The game is primarily a single-player game, but up to three players can participate cooperatively on the same computer or console, each controlling one of the three selected characters.