IMHO.

Single-player games like Rainbow Billy: The Curse of the Leviathan

Below are 13 single-player Steam games similar to Rainbow Billy: The Curse of the Leviathan, 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 Rainbow Billy: The Curse of the Leviathan page.

Ranked picks

  1. 1
    Rizz Dungeon: Skeleton Key to My Heart — Steam game cover

    Rizz Dungeon: Skeleton Key to My Heart

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    Fighting is hard, right? Let your party do it for you! Romance Monster Girls and traverse the Dungeon! Hopefully they'll all get along... right?

    2026ActionIndieAdventureSingle-playerSimilar games →
  2. 2
    The Gardener and the Wild Vines — Steam game cover

    The Gardener and the Wild Vines

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    Leap, slash, and climb your way to the top of magical towers in this wholesome platformer about a gay Gardener on a quest to rescue his love.

    2021IndieAdventure9.99 USDSingle-playerSimilar games →
  3. 3
    People of Note — Steam game cover

    People of Note

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares RPG with Rainbow Billy: The Curse of the Leviathan.

    In this turn-based RPG musical, join Cadence as she recruits an ensemble of musicians on her quest for stardom. Experience turn-based combat like never before, where each battle is a musical performance with evolving combat conditions and genre-bending mashup attacks!

    2026RPG24.99 USDDeck PlayableSingle-playerSimilar games →
  4. 4
    Mythic Mire — Steam game cover

    Mythic Mire

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    A surreal RPG-adventure set in a world between dreams and nightmares. Explore strange environments with your trusty digital Pixie companions.

    2025IndieAdventureRPG9.99 USDSingle-playerSimilar games →
  5. 5
    Siralim Ultimate — Steam game cover

    Siralim Ultimate

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and RPG with Rainbow Billy: The Curse of the Leviathan.

    Siralim Ultimate is a monster-catching, dungeon-crawling RPG with a ridiculous amount of depth. Summon over 1200 different creatures and travel through randomly generated dungeons to acquire resources, new creatures, and loot.

    2021StrategyIndieRPG19.99 USDDeck PlayableSingle-playerSimilar games →
  6. 6
    Celestial Hearts — Steam game cover

    Celestial Hearts

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and RPG with Rainbow Billy: The Curse of the Leviathan.

    Celestial Hearts is a yuri jRPG featuring an ATB battle system and the story of a heartbroken young elf and an angel seeking her life's purpose.

    2021IndieRPG4.99 USDSingle-playerSimilar games →
  7. 7
    Aethermancer — Steam game cover

    Aethermancer

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    Monster Taming meets Roguelite. Become the Aethermancer and fight alongside mythical creatures. Explore the ever-changing Fractured Ruins, plan your moves in challenging turn-based battles, and watch your Monsters grow stronger from previous lives and defy death!

    2025StrategyIndieAdventure21.99 USDDeck VerifiedSingle-playerSimilar games →
  8. 8
    Moonglow Bay — Steam game cover

    Moonglow Bay

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    Embark on a journey as a rookie angler in Moonglow Bay, fulfilling your partner's final wish. Team up with friends, family, and neighbours to hone your fishing skills, nourish relationships, and restore a remote town's fractured community in this slice-of-life fishing RPG!

    2021IndieAdventureRPG24.99 USDDeck PlayableSingle-playerSimilar games →
  9. 9
    Undertale — Steam game cover

    Undertale

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and RPG with Rainbow Billy: The Curse of the Leviathan.

    UNDERTALE! The RPG game where you don't have to destroy anyone.

    2015IndieRPG9.99 USDDeck PlayableSingle-playerSimilar games →
  10. 10
    DELTARUNE — Steam game cover

    DELTARUNE

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and RPG with Rainbow Billy: The Curse of the Leviathan.

    Dive into the parallel story to UNDERTALE! Fight or spare your way through action-packed battles as you explore a mysterious world alongside an endearing cast of new and familiar characters. Chapters 1-4 will be available on launch, with more planned as free updates!

    2025IndieRPG24.99 USDDeck VerifiedSingle-playerSimilar games →
  11. 11
    The Caribou Trail — Steam game cover

    The Caribou Trail

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    The WWI story where your goal isn’t to kill, but to survive. In the still trenches, three soldiers learn the harsh truth of war: reckless missions, digging trenches, collecting dog tags and ghostly whispers in the dark. Home before the leaves fall, they thought.

    2026ActionIndieAdventure11.69 USDDeck VerifiedSingle-playerSimilar games →
  12. 12
    Roots of Yggdrasil — Steam game cover

    Roots of Yggdrasil

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie with Rainbow Billy: The Curse of the Leviathan.

    Build settlements, explore the Nine Realms, collect artifacts and upgrade your deck to reach the top of Yggdrasil in this post-Ragnarok roguelike city-builder! Can you survive the end of the world?

    2024StrategyIndie11.99 USDDeck VerifiedSingle-playerSimilar games →
  13. 13
    Epic Manager - Create Your Own Adventuring Agency! — Steam game cover

    Epic Manager - Create Your Own Adventuring Agency!

    Single-player alternative to Rainbow Billy: The Curse of the Leviathan — playable solo, no multiplayer required. Shares Indie and Adventure with Rainbow Billy: The Curse of the Leviathan.

    Epic Manager is a unique crossover between Sports Management and classic JRPGs. Experience an addictive “one more turn” mix of tycoon strategy, roguelike elements, roster management, combat and character progression, all rooted in an epic yet light-hearted fantasy setting. Rated ‘E’ for EPIC!

    2016StrategyIndieAdventure17.99 USDSingle-playerSimilar games →