This Oxygen Not Included-style survival city builder is also a rat-themed colony sim with some unexpected Terraria vibes, and you can try it free

Ratopia art — (Image credit: Cassel Games)

The wizards at Don't Starve developer Klei Entertainment helped write a new playbook for colony sims with the release of Oxygen Not Included, and Ratopia has taken a few pages from it and gone off in an adorable direction of its own. It's a survival city builder that hit Early Access last month, and I'm mighty impressed with the demo so far, which is also giving off some unexpected Terraria energy.

Ratopia's user reviews – which are 88% positive at the time of writing – draw countless, understandable comparisons to Oxygen Not Included. Both are 2D colony sims about gathering resources, assigning jobs to citizens, building facilities to process and generate goods, and researching new technologies that enable further expansion. You recruit more people to do more stuff and you need more stuff to keep those people happy and alive. Round and round the progression curve goes, and boom, there goes eight hours in the blink of an eye.

So far, so colony sim. The thing that really makes Ratopia pop in my eyes, based on my brief time with the free Steam demo, is the wrapper on this familiar formula. The rat motif is adorable, for one, and translates well to cute little facilities and farms and burrows. The way you engage with the world is also surprisingly Terraria-like at times, which I find exciting.

There's a very basic action component, and something about the way you explore environments, mine resources, and arrange layered habitats connected by ladders and lifts really hits the Terraria nerve for me. I expected Oxygen Not Included vibes, and Ratopia feels like home in a different sense too. There are even intermittent waves of enemies that besiege your base, which leans more into the array of defensive structures.

My experience has been brief but positive, and comments from veteran players as well as features shown in trailers suggests there's surprising economic and political depth to Ratopia's late-game. If I have any criticisms of my own at this stage, it's that the English translation is still a little rough in some areas, particularly in the descriptions for each citizen's unique passives. The intro experience is also a little cumbersome, but the game quickly opens up once you get some citizens in and learn how to assign them. Give it a go, and I'd say give it at least 30 minutes or so. Just be warned that demo saves may not transfer to the full game.

If you're more of a mouse person, have a gander at this turn-based RPG where a pocket knife-wielding mouse fights cats.

Austin has been a game journalist for 12 years, having freelanced for the likes of PC Gamer, Eurogamer, IGN, Sports Illustrated, and more while finishing his journalism degree. He's been with GamesRadar+ since 2019. They've yet to realize his position is a cover for his career-spanning Destiny column, and he's kept the ruse going with a lot of news and the occasional feature, all while playing as many roguelikes as possible.