Man, there's a lot of stuff going on. The concept for this game is so cool. The game is pretty tough to get into, but you figure it out after a little while. The first time reading the tutorial didn't really help me, but I read it again after building like 3 things and it made a lot more sense. You mostly figure out the game as you go.
The art for everything was great. The dotted lines for the orbit were nice, the orange line was so helpful for finding where the outer planets currently were. Pixel art animal forms for each of the planets is a really neat idea that adds a lot of charm to the game. The art for the elements is sweet and pretty unique with their particles that trail behind them. I like how unique the 5 little wedges that make up the outline of them are. Same with the cool ring of the crafting areas for the planets. They could have just been simple circles, but you made them unique and it looks so much better for it. The colour palette for the different types of elements was pretty good. It was easy enough to tell what type every little orb was just from a glance without having to zoom in to read its name. The particles fading to a slightly different colour is subtle effect, but quite nice.
The text was a nice font and the gradient colours look great, but the font size was just too small for the requirements for the planets and the names of the molecules. The little trivia things for the planets is neat, but a lot of the text doesn't fit inside the boxes.
The springiness of the molecules is frustrating pretty much the whole time. Moving them takes so much longer than it really should. You have to click on it, then move your mouse to where it needs to go, then hold there for like 5 seconds until it stops bouncing around before you can let go and go grab another one. I think it's a really great effect and makes thematic sense with planets and gravity, etc., but I just think it's a little overdone. The planets repelling their building blocks makes it so hard to build the last 3-ish planets. It's doable with the first 6, but once you get 8-10 elements, it's difficult and tedious to build them.
Everything about this game was so clean. The UI all looks great, the gameplay was simple enough - just smash the ingredients together to create everything, the music is just relaxing and doesn't get in the way and fits the game, etc.
All the planets are pretty cute, but Saturn mew-mouse was my favourite.