Single-player games like Under the Ruin
Below are 8 single-player Steam games similar to Under the Ruin, 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 Under the Ruin page.
Ranked picks
- 1

Zombie Apocalypse - The Last Fortress
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
Defend your base against hordes of zombies while using a variety of weapons, vehicles, explosives, soldiers and turrets in this survival tower defense game. Will you be able to create your own strategy and survive for 30 days?
- 2

Zombie Apocalypse - The Last Defense
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
Create your own strategies, tactics and manage your resources in this survival tower defense game. Buy weapons, vehicles, explosives, soldiers, turrets and battle against huge waves of zombies. Can you survive for 25 days?
- 3

THE LAST DEFENSE!
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
A classic tower defense game with ordinary graphics didn't fascinate you? Well, let's give a try and see how long you can defend! Show your commanding skills and prove no enemy can break your defense! Be a hero and save humanity with the LAST DEFENSE!
- 4

ByteCrawler
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy with Under the Ruin.
Pick a hero, build your swarm, and hold off enemy waves. Place units, watch your energy, and level up to survive in this lane-defense strategy game!
- 5

ITER-8
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
Welcome to the surface, ITER employee #8. Mine the Pillar, upgrade your tools, defend your base, reach the top... or die miserably. Each expendable worker pushes the mission forward - one glorious, replaceable iteration at a time.
- 6

Legendary Hoplite
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
A combination of Action RPG and Tower Defense: slay monsters, find weapons, upgrade your armies, defend your base… Prevent humanity from extinction at the hands of monsters from Greek mythology and ancient tribes. Don't let them cross the gate, commander!
- 7

Phantom Brigade
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Indie with Under the Ruin.
Phantom Brigade 2.0 is a cinematic, tactical mech strategy game with a revolutionary timeline-based command system. See the future, predict enemy actions, and plot your counterattack on the timeline! Recruit and level up your squad of rebels to retake war-torn Fyrland from the Kaskad occupation.
- 8

Envy the Dead
Single-player alternative to Under the Ruin — playable solo, no multiplayer required. Shares Strategy and Simulation with Under the Ruin.
Envy the Dead is zombie survival roguelike, in which you are leading group of unique, randomly generated characters through destroyed lands, infested with zombies.