Single-player games like What The Fortress!?
Below are 10 single-player Steam games similar to What The Fortress!?, ranked by player overlap. Every pick carries Steam's Single-player category, so multiplayer-only titles or always-online games don't sneak in. imho.run pulls the category data from Steam directly — Single-player here matches what the store labels.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like What The Fortress!? page.
Ranked picks
- 1

Rogue Kingdoms
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Classic tower defense meets roguelike adventure where you control the hero! Dive into procedurally generated levels filled with unique waves of enemies. Create powerful synergies with a variety of game-changing skills, relics, weapons, and traits to defend your kingdom. Every run is a new challenge!
- 2

Gem Tower Defense 2
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Gem tower defense is different from general tower defense games. The map of gem tower defense is extremely open and free. Players need to constantly plan and build labyrinths to delay the advance of waves of monsters hitting the fortress.
- 3

Stronghold Defenders
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Casual with What The Fortress!?.
Gather and manage resources, defend your stronghold, explore and expand your kingdom and fight back against corruption.
- 4

MoonBeam
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Here's a special forces team for you, they all have unique skills. Your task is to make the enemy die in a designated place. Get more energy.
- 5

Zakantosh Cardgame
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
A Collectible Single Player Card Battle Game that focuses on Story Content. Your enemies are all kind of creatures, goaded by the evil influence of the mysterious crystals, that appeared out of nowhere. You will need to collect powerful cards and gems to fight your way through Zakantosh.
- 6

Relic Guardian - Tower Defense
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
"Relic Guardian" is a fantasy style strategy tower defense game. As the builder on the battlefield, summon a variety of defense towers and spells with reliable hero companions to complete this epic and guarding adventure!
- 7

Luckitown
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Luckitown is a turn-based tower defense where you roll dice to build new structures and cast spells to defend your town.
- 8

Rogue Tower
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Casual with What The Fortress!?.
Rogue Tower is a tower defense game with roguelike elements and a continuously expanding path which you can influence. Unlock, build, upgrade, expand, defend.
- 9

Kingdom vs Zombies
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Build a flourishing empire, equip powerful armors and improve your character!
- 10

Virus Madness - Dungeons of your Body
Single-player alternative to What The Fortress!? — playable solo, no multiplayer required. Shares Strategy and Indie with What The Fortress!?.
Fight your way through vicious viruses, bacterias to save all humanity in this cute shooter game. Advance through dungeons of your body and destroy them all