
Rat Overflow is an adorable rat breeding simulator about genetics, glory, and having way too many rats. Develop your show winner bloodlines and breed thousands of unique rat coats!
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Rat Overflow is a deceptively cute rat breeding simulator about genetics, glory, and having way too many rats.
Breed fancy rats with a realistic color genetics system, show them off in competitions, and try to keep track of your ever-growing colony. Pick your pairings carefully — or don't — and watch the pups grow into champions, beloved pets, or delightful genetic surprises. With thousands of possible rat appearances driven by real inheritance mechanics.
Start with humble stock, outcross from five quirky NPC breeders — each with their own color specialties and personalities — and build bloodlines that dominate the show circuit. But be warned: Rats breed fast. More pups are on the way. They're always on the way.
Enter your best rats in shows against rival breeders, win championships, and level up to unlock new breeders with new color varieties and better genetics.
Over a dozen genetic loci control color, markings, health, and conformation. Siamese, Russian Blue, Dumbo ears, Rex coats — it's all in the genes. Breed strategically, or discover what happens when you don't.
Buy outfits and accessories to style your rats for photo ops. Express yourself. They're your rats now.
Realistic genetics with 14+ loci and thousands of color/pattern combinations
5 NPC breeders to unlock, each with distinct specialties
Multi-tier show system with rival competitors
Health and conformation genetics — longevity and show success are inherited
Pastel retro aesthetic with pixel art and a Windows 98-inspired UI
A gentle but persistent sense that you have too many rats
The game's code is written with significant help from AI.
Some text in game, as well as text on the store page is written with AI assistance.
All graphics in the game are and always will be painted and edited by me without any use of generative AI. Same goes for all graphics on the store page and other marketing.
Genres
Stats
All-time low is the lowest price we've recorded for this game since we started tracking it.
Languages: English
Engagement
Hours played at review time, across 40 reviews with recorded playtime.
Reviews
Themes across 40 recent reviews and how positive each mention is. A keyword signal, not full sentiment analysis.
positive critical· bar length = how often the theme comes up
Reviews
I'm sad to give this game a negative review. I was completely unable to breed any rats in the game, leaving the game completely unplayable. I suspect it has to do with the fact the game is vibe coded with AI. I've requested a refund. It's a shame, I love genetics games (nearly 600 hours in Niche alone!), and I'm new to rat genetics so I was hoping to learn through gameplay. With a poor first impression and low trust in AI, I'm not willing to stick around to find out if the game becomes (and remains) stable enough to play.
Love, love, love this little game so much. It's so informative and educational, while also having so many wonderful babies!!! One little gripe though, and this is 100% ONLY ME saying this. But could there possibly be an option in the future to turn off death and getting rid of the euthanize button? I know it's realistic in the life stage sense, yeah, but one of my goals is trying to get the exact coat of the ten rats I've had in my life. I've already lost all my babies once and losing them a second time, even virtually, makes my belly hurt.
I wouldn't really recommend this game in the current state. While the genetics are in depth and realistic - the management of the rats leaves a lot of improvement. You cannot pause and manage your rats at the same time. If you pause you are only allowed to read the game wiki. Odd choice for a single player game. If you mark rats for sale in your litter and you would like to do it all at once - better be quick about it. If you just have them selected before clicking "mark for sale" and the day goes on to the next one (remember you cannot pause while you do this) it will simply deselect your selection. There is no indiciation on when a day will go over to the next one. You can change the game speed but unless you keep checking the date you can't tell how fast it actually is. If you use a bigger font you have to check if your rats are male and female because the icon gets pushed out of view as well
for the rodent enjoyer and number fanatic, the rat mom and 9-5 worker, the person who loves statistic and probabilities; i think this game will be for you. After playing Mewgenics for a little bit, and playing a lot of breeding online games such as Cromimi and Howrse, I needed to scratch the ''genetics'' and ''casual'' itch in my brain. After seeing this game in one of my rat care groups, I was absolutely hyped. It hit all the spots I craved from a game these days, I didnt want to fight to get better genetics, I wanted to do it myself either by shows and training (like Howrse) or bloodline (Cromimi). The sprites are cute and colorful, you can change the UI per your preferences and there is an accessibility feature for dyslexic folks. Easy to progress but you can bottleneck your genetics quick if you do not do the linebreeding technique and want all green stats rats. Money might be hard to get when you are bottlenecked which you end up making ''incest litters'' to sell and make enough to keep those who are show worthy in shows and retired ones not suffering. I wish there was more flexibility with the sick rats, in the fact of giving comfort care before euthanazing. Especially when player does not have money to euthanize but know they can do comfort care, I think for IRL rat owners it is kinda distressing. The game is a good representation of everything rat breeding, from bad genetics to perfect breeding. I will give to this game, you gotta use your own morals. From deciding if you want to inbreed for perfect rats or not, to struggling to euthanize those who are sick because no more money is coming in from a genetic bottleneck. I absolutely love this game and will follow it's development.
As someone who has loved games where your animals reproduce and have descendants based on their genes, from Petz 5 to Lioden and a million ones in between, this scratches that itch!! I love the depth of the genetic system and how realistic it makes things. And not only is the art of these little rats adorable, but so are the names, haha!! I definitely recommend giving the game a try. It's already addictive, and this is just the early access version! :)
Help I just spent 10 hours breeding digital rats
As one who constantly searches the Internet for all kind of games with a focus on genetics, breeding and mutations, this is a hidden gem. - Straight to the point, no other nonsense, just breeding and genetics at play - Nearly infinite possibilities thanks to the many varieties obtainable and the offspring rating system, despite focusing on just one genus (rats) - Very realistic when it comes to how the various aspects (genes transmisson, COI, varieties, rating of "beauty standards" of offspring, illness and death) are handled - while breeding is the focus, gameplay allows for different directions: you can choose to simply raise your favourite rats, or aim to collect every single variety and mutation, or even breed to push stats to excellency - Trying to breed the perfect offspring with the perfect stats is addicting and challenging, providing hours of gameplay if you decide to go that route. After almost 4 hours I'm still trying to get more than two "excellent" stats in one single unit. The choice of 2D pixelated artstyle is the perfect one for these types of games. It results in a very cute and relaxing looking game while still realistically conveying the characteristics and peculiarities of the varieties. Overall so much better than a lackluster 3D approach that 9 out of 10 times produces uncanny and ugly results that are painful to watch. I hope to see more games of this same kind from this dev, maybe focusing on another type of animal... dogs? cats? a species of bird (hummingbird?) or fish (koi?) with many subspecies/varieties? .....I don't dare hope for snakes since I get the feeling Dev indeed has pet rats and there's no love between snake owners and rat owners T_T
Literally perfect itch-scratcher if you love genetics/breeding games. No notes. 10/10
I told myself I would somehow manage to name the rats myself, similar to how Quarter Horses function (clever combos of parents/grandparents' names), and now I'm 200+ rats deep, have allowed the random names to live their best lives, and Crusty Sploot is my reigning champion. 11/10, I need more rats
I love rats and I love genetics, I am the target audience. So far I've yet to run into major issues except leveling up is extremely hard and you need to level up to get into new shows and new stock breeders. Another complaint I have is that there doesn't seem to be an option to take the rat to the vet if it's got URI issues for example it seems the only option is to euth them for 20 currency.
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Trends
Concurrent players on Steam, sampled daily since tracking started.
Momentum
Pace estimated from the game's recent review growth (our daily snapshots) at its own sales-per-review ratio — a momentum signal, not booked sales.
Audience
Estimated from the language of this game's reviews — a proxy for where players are, not official Steam demographics.
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