Color Toy Sorting - Hoop Stack is a free puzzle game developed by Onibit, available on Android. The objective of the game is to stack hoops of the same color on top of each other. The game is easy to play, with simple one-finger controls.

The game features over 5000 levels, with more levels continuously added. Players can enjoy the game at their own pace, as there is no time limit. The game also offers a variety of themes and tubes to keep the gameplay fresh and exciting. Best of all, the game is completely free to play, with no in-app purchases required.

Overall, Color Toy Sorting - Hoop Stack is a fun and addictive puzzle game that is perfect for players of all ages. With its colorful graphics, easy controls, and endless levels, it's a game that you won't be able to put down.