Games like Ruins
Games like Ruins include Terraria, Cosmoteer: Starship Architect & Commander, Oxygen Not Included, Among Us, and Plague Inc: Evolved. We matched them by the tags players give Ruins on Steam (Strategy, Party Game, Exploration, 2D, and Survival): closest matches first, and among equally close ones the better-known games.
Terraria
Shared: Survival · 2D · Exploration
Cosmoteer: Starship Architect & Commander
Shared: Strategy · 2D · Singleplayer
Oxygen Not Included
Shared: Survival · 2D · Singleplayer
Among Us
Shared: Survival · 2D · Party Game
Plague Inc: Evolved
Shared: Strategy · Singleplayer · Indie
Don't Starve
Shared: Survival · Indie · Singleplayer
The Escapists
Shared: Strategy · 2D · Singleplayer
Bloons TD 6
Shared: Strategy · Singleplayer · Multiplayer
Subnautica: Below Zero
Shared: Survival · Exploration · Singleplayer
Dune: Awakening
Shared: Exploration · Survival · PvE
RimWorld
Shared: Strategy · Survival · Singleplayer
Don't Starve Together
Shared: Survival · Multiplayer · 2D
ShellShock Live
Shared: Strategy · 2D · Multiplayer
Barotrauma
Shared: Survival · 2D · Multiplayer
The Long Dark
Shared: Survival · Exploration · Singleplayer
Rain World
Shared: Exploration · Survival · 2D
Town of Salem
Shared: Strategy · Multiplayer · Indie
60 Seconds! Reatomized
Shared: 2D · Strategy · Exploration
Subnautica 2
Shared: Survival · Exploration · Multiplayer
Plants vs. Zombies GOTY Edition
Shared: Strategy · Singleplayer · 2D
The Escapists 2
Shared: Strategy · 2D · Multiplayer
Hollow Knight: Silksong
Shared: 2D · Indie · Exploration
Dungeon Defenders
Shared: Strategy · Survival · Singleplayer
Sons Of The Forest
Shared: Survival · Multiplayer · Exploration