Underkeep

Underkeep is a tower defence game that reverses the usual perspective. Rather than controlling the attacking side, the player is the final boss of a labyrinth and must stop adventurers from reaching the boss room. The player digs corridors, positions monsters and lays traps, and anything placed remains in position after a wave ends, so the labyrinth develops over the course of a run.

The game offers 15 monsters, 12 traps and 8 special zones. Walls can be used to fold the path back on itself so that a single trap affects adventurers more than once. Each wave shows in advance which classes of adventurer are approaching, and different classes behave in different ways: miners break through walls, sappers disable traps and rogues can sometimes pass through them. Adventurers also have either a physical or a mental weakness, so a warrior may resist blades but be vulnerable to mental attacks while a mage is the reverse, and gold must be spent accordingly. When a class appears for the first time, the game pauses and displays a card describing it and its weaknesses.

Defeat removes the current labyrinth, but a record of progress is kept between runs. Controls use the mouse for placing and removing items, with keyboard shortcuts for starting waves, opening the shop, expanding land, moving the boss room, rotating items and adjusting game speed. Korean, English and Spanish are supported. The game has now been released on Steam and has one user review at the time of writing.