Single-player games like Ostallian Core
Below are 8 single-player Steam games similar to Ostallian Core, 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 Ostallian Core page.
Ranked picks
- 1
Space War: Infinity
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Vertical semi-procedural shmup with upgrades, real-time enemy waves, and infinite replayability. Level up your ship, unlock 20+ weapons, defeat 5 bosses, and survive endless bullet-hell combat.
- 2
Blacksea Odyssey
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Enter the Blacksea Odyssey, a violent top-down rogue-lite space shoot ‘em up RPG brimming with colossal creatures and runic technologies. Explore dangerous, interstellar spacescapes as you hunt enormous space-behemoths with a harpoon and rune-infused spears.
- 3
Flame Over
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Blending top down "squirt em-up" action and "Pyroguelike" game mechanics, Flame Over features fast-paced fire-fighting thrills, randomly generated levels, 4 different game zones and dastardly hazards at every turn!
- 4
Run Build Pew!
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
You’re being Bounty-Hunted! Run, Build your ship piece-by-piece and make it work with the parts you find, Destroy outposts and waves of fleets, and Pick your battles carefully to overcome your hunters in this Fast-Paced Top-Down Action Roguelite Shooter.
- 5
Crimsonland
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Thousands of aliens, giant spiders, mutant lizards, and more are on the attack - can you survive the onslaught? Crimsonland is a top-down shooter with a touch of RPG. Unlock over 30 weapons and over 50 perks from quirky to brutal. Complete the quest and show your skills in five survival modes.
- 6
ARRIVAL: ZERO EARTH
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Fight giant War of the Worlds -style aliens invading Finland during a Winter in the 90's. Build an army of local townspeople in this chaotic semi-autobattler roguelike. Navigate through different biomes to obliterate the aliens from cosmic dimensions.
- 7
Earl vs. the Mutants
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Adventure with Ostallian Core.
Save humanity in a mutant-ridden apocalypse! Dive headfirst into Earl vs. the Mutants, a high-octane top-down survival action-roguelite set in the aftermath of a nuclear apocalypse.
- 8
City of Beats
Single-player alternative to Ostallian Core — playable solo, no multiplayer required. Shares Action and Indie with Ostallian Core.
Shoot. Groove. Loot. Repeat. Cross an ever-changing city skyline, flowing through encounters in tune with the cityscape’s beat. From the weapons you fire, to the enemies you shoot, to the zen-like flow, the only way to win is to become one with the beat.