UnderDark: Defense Steam Demo Review
Verdict: Maybe
UnderDark: Defense has a solid core buried under an unfinished mobile port.
UnderDark: Defense is a Roguelike Tower Defense game from Korean developer FreeDust. It looks good, plays well, and has a core loop that is easy to enjoy. It is also a mobile port that has not made the jump to PC properly, and that is the reason it sits at Maybe rather than Play. There is a good game in here. Come back when the port is finished, or go in knowing you will need patience.
UnderDark: Defense is a genuinely enjoyable tower defense game with a strong card-driven loop. The port is unfinished, with real technical problems that affect basic playability. Come back when the port is fixed, or go in knowing patience is required.
Pros
- Satisfying tower placement and path manipulation
- Card system adds meaningful choices
- Deals mechanic creates interesting trade-offs
- Plenty of customisation options across heroes, towers, and weapons
Cons
- Screen cannot be resized, causes UI issues across monitors
- Mouse clicks and controls unreliable
- Some defences not rotated to match PC map layout
- Difficulty does not ramp up enough to sustain engagement
Port Problems
The port problems are worth naming clearly because they are not minor. The screen cannot be resized, which meant playing across two monitors with part of the UI cut off. Mouse clicks and controls did not always register.
The map has been rotated for PC but some of the defences have not been updated to match, so they point in the wrong direction and cannot actually be used. These are not polish issues. These are fundamental PC support that is not finished.
Core Loop
You are defending a fireplace from waves of enemies that approach from outside the map. You cannot fully block the path. The game requires you to leave a route open, so the whole strategic problem becomes about making that route as long and painful as possible. The longer the enemies spend walking, the more time your towers have to deal damage. Building that path is the interesting decision, not just placing towers in front of the entrance.
Cards drive the progression during runs. Kill enemies, collect XP, level up, pick a card. Cards can be placed as new towers or used to upgrade existing ones. The buff system adds another layer: choose one of three buffs after each wave, stacking things like attack speed increases or hero health boosts.
The deal mechanic is the most interesting wrinkle. The game offers trades: take a negative effect, like a 20% increase to boss health, in exchange for extra cards or rewards. The difficulty was not high enough to make refusing these feel necessary, so accepting almost all of them felt like the obvious call. Whether that changes in later content is something the demo cannot answer.
Standout Moment
The favourite moment came from stacking Paladins in a choke point. Call it a slap zone. Everything that walked into it died before it had moved three steps. That kind of emergent satisfaction, finding a position on the map that turns the route into a one-way destruction corridor, is the game at its best. The hero can attack too, but with a slap zone operational the hero becomes largely decorative.
Metagame and Verdict
The metagame outside of runs is extensive and screams mobile-first design. Equipment slots for helmet, main weapon, ring, secondary, and others. Heroes with individual level-up paths. Pets. Inventory management with rarity tiers from Common to Rare. Crates in the shop with timers on them.
You can feel exactly where the microtransactions used to live. On mobile UnderDark: Defense is free to play with optional ads. On PC none of that applies, but the structure remains and it makes the outer layer feel designed for a different context. It does mean there are a lot of options for tower and hero loadouts if different playstyles appeal.
100 minutes in and there was still more demo to explore. The difficulty needs to ramp up significantly to keep the Tower Defense loop interesting long term. The eight Steam reviews at time of playing were all positive, and the core deserves them. The port does not yet.
Game Info
- Developer
- FreeDust
- Publisher
- FreeDust
- Expected release
- Q1 2026
- Platform
- PC, Mac
- Multiplayer
- No
- Controller
- No
- Playtime
- 1h 40min
Watch the video review: YouTube
Tags: Tower Defense, Deck Builder, Roguelike, Strategy, Multiplayer, Action, Casual, PvE, Adventure, Indie, Survival, Steam Tower Defense Fest 2026
Appears in
- Steam Tower Defense Fest 2026: Steam Tower Defense Fest runs until March 16th and throws a lot of demos at you. I played three of them. One has two battlefields running simultaneously, one is a mobile port that somehow still works, and one looks like someone spilled Skittles on a fantasy battlefield. Here's what's worth your time.
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