It would be nice if there was some calm music in the background. Potentially even having different tracks for the different areas.
I feel like the level progression could use some work. The last two levels of the hatchery were the only ones that I had troubles with. Those felt like a jump up in difficulty compared to progression of all of the other levels.
I think that the Commons could use some work. Once you figure out who likes who and that happy cheers up grumpy it is mostly just the same thing but with more blobs. Potentially having more colors and more moods, so that it keeps the same concept but remains more interesting.
Overall the Nursery and the Reef felt pretty good, although they were all mostly easy. The one thing that I felt kind of sad about was that in the Reef you could not feed all of the creatures, and so some would still be hungry at the end of the level. :(
I found being able to play with the physics to be fun. That made me think that you could potentially make a set of levels that use physics.
Overall this game seems pretty good and I look forward to seeing it come to Steam.