Slime Castle — Idle TD Game

Contains adsIn-app purchases
67.5K reviews
Content rating
Rated for 3+
1M+
Downloads
Content rating
Rated for 3+
In-Game Purchases (Includes Random Items)
Learn more
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About this game

The bad humans are invading the mysterious forest! The slime kingdoms in the forest are facing a tremendous crisis!

As a slime chosen by the Slime Sage, you can enhance your abilities through battles, collect legendary equipment, utilize powerful skills, defeat waves of terrifying enemies, and safeguard the peace of the forest.

Once you are defeated, come back stronger!

Slime Castle is a role-playing idle tower defense game.

Players could enjoy an excellent role development system, countless powerful weapons, and several impressive battle scenes.

==== Game Features ====
-Auto-battle system with simple idle clicker gameplay. Enjoy a delightful time!
-Many distinctive maps and different enemies with unique skills. Explore more secrets of this world!.
-Flexible and diverse upgrade system. Build your exclusive fortress!
-Collect mighty equipment and level up the adorable slimes. Experience an extraordinary adventure!
-Abundant free rewards to claim. No need to worry about gold anymore!
-Set battle strategy by combining fortress, equipments, and control enemies. Find the optimal methods to defeat your enemies!

Now let‘s start the epic idle adventure and embark on the path to become the greatest Slime Hero!

Experienced a problem? Got a suggestion? You can reach us at slimecastle@redtailworks.com
Become a Slime Hero! Defend forest against human invasion in the idle TD game!
Updated on
Sep 29, 2026
Available on
Android, Windows*
*Powered by Intel® technology
Events & offers

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    Location, Financial info and 3 others
  • This app may collect these data types
    Location, Financial info and 3 others
  • Data isn’t encrypted
  • Data can’t be deleted

Ratings and reviews

65.1K reviews
Dustin Hardin
October 10, 2025
Update: They recently changed the mini games to be much more difficult so that they could sell their new mini game passes. I recommend not playing 🙏 Not F2P friendly. Decent fun for outrageous prices. Want a better (or new) character? You need to drop more than $30 for each one. There is only one high-ranking slime available for F2P players. The pull rates for upgrades are incredibly low considering the price they want you to pay.
92 people found this review helpful
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Azur Interactive Games Limited
August 19, 2025
Hello! Making in-game purchases only speeds up your progress, it's not the only way to get ahead in the game. There are plenty of other ways to earn in-game resources. So, if you're an active player, you can still compete with others. Good luck!
Amonimus
September 27, 2024
At the current stage nearly everything is maxxed out and am still getting one-shot by the boss, and sometimes by regular enemies due to RNG. Since gold now has little use, the only way to do any progress is either log in regularly for months for very rare resources, or buy them, as upgrades now expect more investment than how much it took to get so far. So a fun ride, but not a very long one due to exponential difficulty and idle element prividing too little.
5 people found this review helpful
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Azur Interactive Games Limited
October 8, 2024
Hello! We are working on fixes, improvements and new content, and we hope that you will like the game's next updates.
Dyandrea Phoenix
October 5, 2024
The ads in the game are so frustratingly annoying. There are ads for everything, including increasing the level's speed to 3x. This would be fine if the ads weren't so extremely sensitive that you are almost always guaranteed to accidentally click on the ad, instead of closing it out. And if you do accidentally click on the ad and get taken out of the app, it will restart entirely and you do not receive any of the level goodies, which is more irritating when you are halfway through the level.
84 people found this review helpful
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Azur Interactive Games Limited
October 8, 2024
Hello! Ads help us to keep the game free. Thank you for understanding!

What’s new

1. Global-2 Adventure Card and Slime Skill unlock/advanced mechanism adjustments
2. Removal of the slime mutual exclusion mechanism among Expedition, Pickaxe Transport, and Travel Mode
3. Fixed known issues