Down the Oubliette

Down the Oubliette is a tower defense game where a girl plunges deeper and deeper into the haunted floors beneath a country house. Floors are randomized each run and the player must dig through dirt to uncover the spirit spawners, after which the ghosts will chase the player and the placed towers must be used to wear them down. The player can only see so much of the floor with the ambient light that follows them, but a radar helps them figure out which dirt may contain spirit spawners.

There are sixteen floors to a run with each thematic level consisting of four floors. Players can place four towers using the energy earned after clearing a wave of spirits, the beacon gradually wearing down ghosts with light, the coil zapping them with electricity, the fan holding them back a bit, and the torch emitting a stream of fire. Certain spirits are weak to specific tower types and towers can be upgraded to increase their effectiveness with crates found in certain stages.

The player can restart failed floors with impunity but will have to try again if they lose all of their character's hearts. Hearts replenish between floors and the tower-building energy is carried between them, and since players dig away the dirt to open up walkable areas, they can somewhat customize the path spirits will take when trying to reach their character.