Best Games Like Radiation Island

Dude Simulator is an open world sandbox game. This is a life simulator. The main objective is to enjoy what you are doing.

Force of Nature is an indie open world sandbox game with fighting, crafting, building and farming systems.

Set in a sleepy American country town in the 1980s, American Fugitive invites you to play as Will Riley. You're no angel, but you're not a killer. Yet the cold-blooded murder of your dad is the crime they've locked you up for.

Hardcore medieval multiplayer sandbox with terraforming, free preset and modular building construction, rich crafting (smelting, forging, farming, animal breeding etc.

Empyrion - Galactic Survival is a 3D open world space sandbox survival adventure. Build mighty ships, menacing space stations and vast planetary settlements to explore, conquer or exploit a variety of different planets and the allegedly empty space!

A New Land, A New Life: Savage Lands is a gritty, brutal, first-person open-world fantasy survival experience in which players have only one goal: Stay Alive.

Miscreated is a multiplayer online hardcore survival game set in a post-apocalyptic future. You will need to survive against mutants, players, and even mother nature herself.

Citadel: Forged With Fire is a massive online sandbox RPG with elements of magic, spellcasting and inner-kingdom conflict.