Puzzle games are some of my favorite types of games, and I'll often play them when I need to unwind and relax. I had a lot of fun with this one.
The rules were clear and easy to understand. The blobs were easy to pick up and place where I wanted to. I liked how you slowly unlocked the rules as you played, letting the players figure out how the blobs interact with each other by playing. The Notebook was very handy to be able to double check how different things worked together. I also really liked that instead of just showing the first combination I got, it showed multiple combinations. There were times I made combinations that I knew wouldn't help solve the puzzle just to add another one to my Notebook.
The level progression felt good. The Hatchery, in particular, did a good job of introducing new concepts and challenges, though I think they all worked well. The Hatchery was the world I most often had to stop, think, and experiment to solve some of the levels. I liked how you sometimes included things that weren't needed to solve the puzzle. The Commons was the easiest of the worlds. Once I got the basic concept down, it was a lot of just doing the same thing over and over. You may want to think of ways to add more to the Commons, as it was overall less interesting than the other three worlds. The Nursery and Reef both had some really cool ideas and were fun to solve.
The blobs are super cute. I liked how the blobs in each world had a different look and feel to them. It helped make each world feel unique beyond just the puzzle solving mechanics. The blobs in the Reef were particularly fun to me. They remained me of underwater creatures, which really fit with how they interacted with each other. I liked the way the blobs would interact with each other when they were at the bottom. The little hearts when you placed two happy blobs that got along next to each other was delightful, and the disapproving look when you placed two blobs that didn't was a nice touch. The interactions in the Reef were great as well. It was sometimes fun to move the blobs around to see at the bottom just to play with that.
I really liked that you included a Light and Dark themes. I played all the levels using the Dark theme, as I tend to prefer that look. I also did a few of the levels using the Light theme, just to see how things looked. Everything was clear and easy to read, see, and understand on both themes, and it doesn't feel like the game favors either option.
The SFX were cute and worked well. I liked that each space you could put a blob into had a different sound. I would sometimes play with the order I put the blobs in to make different sound combinations. I'm torn on whether or not I think the game could be improved with the addition of background music. On the one hand, it is a little quiet when you aren't actively interacting with the blobs. On the other, it allowed the SFX to stand out a bit more. I think it you were to add music, it should be something fairly calm and quiet, and should have the option to adjust its volume, including muting it, separate from the SFX volume.
Overall, I really enjoyed playing this and plan to wishlist it on Steam when I can.