I really like the aesthetic of the main menu, it’s very well done. In general, the visuals of this game are charming and pleasant to look at, and the soft background music makes it a very relaxing experience.
Other than that, It’s hard to know what to do at first, I personally felt quite lost until I paused the game and saw the tutorial. Maybe that option should be more readily accessible so that there’s more context while playing.
Also, the game requires certain level of previous knowledge from the player and that creates an entry barrier for people who don't have that knowledge, which is a shame, because I think this could be a very interesting educational game. It would be awesome if there were some sort of training mode or something, where, for example, the game showed you the composition of an element for a couple of seconds and then you had to remember it in order to place the right amount of particles at the right place, or something like that.
Overall, I believe there’s potential here for something that has a well-balanced mix between entertainment and education, and I would have definitely played the game more if I had the necessary knowledge or if that knowledge wasn't required to play it.