Planned Release Date: Sep 8, 2026

About This Game

This time, you are the final boss.

Adventurers are marching into your labyrinth. You are the one who has to stop them.

Dig the corridors. Stand your monsters. Lay your traps. Make the walk to the boss room the worst journey of their lives. Everything you place stays after the wave ends — the labyrinth becomes your design, one wave at a time.

What you actually do

You build. 35 monsters, traps and special zones. Fold the path back on itself with walls and the same trap earns its cost several times over.

You read. Every wave tells you who is coming before it starts. Miners smash your walls. Sappers defuse your traps. Rogues sometimes walk straight through them. Seeing what is coming and rebuilding for it is the game.

You choose: body or mind. Every adventurer has a weaker half. A warrior shrugs off blades but breaks under a whisper. A mage is the opposite. What you spend your gold on decides how far you get.

You lose, and you go again. Defeat takes the labyrinth with it, but the record stays. The next run goes a little further.

The first time a class walks in, the game stops and shows you a card explaining it — including what it is weak to. Read it and prepare.

Controls

[list]

Left click — select and place (drag to place a run of them)

Right click — remove (drag works too)

Space — start the wave

S — shop · G expand your land · B move the boss room

R rotate · F1 game speed · Esc settings

In the shop, left click a card to select it and click again to buy. Right click looks without buying.

From the developer

It started with a question: in every tower defense game I was the one attacking — what does it feel like to be the one holding the door? So there is no hero here who gets stronger. There is a labyrinth that gets sharper.

Korean, English and Spanish are supported.

Play it, and please tell me what feels wrong.

AI Generated Content Disclosure

The developers describe how their game uses AI Generated Content like this:

Underkeep's visual assets — character and monster sprites, traps, tiles, effects, UI art, and store artwork — were produced using generative AI image tools. The developer selected, adjusted, and quality-checked every asset before it went into the game.

The English and Spanish text was machine-translated from the original Korean.

Parts of the source code were written with an AI coding assistant, under the developer's direction and review.

Music and sound effects are not AI-generated. They are human-made CC0 assets from Kenney and OpenGameArt, and the in-game font (Galmuri) is a human-made open-source font.

Underkeep does not use generative AI while you play. The game runs fully offline and generates no content at runtime.