This looks absolutely beautiful and the mechanics seem quite complex and interesting. The problem is just in the way the mechanics are presented and explained by the ui. It's quite unintuitive and could possibly be solved with more detailed tutorialization, but I think it's more about how the information is presented to the player. The slots with "+", "-" and "=" seem to imply that you're trying to get the equation to come out to a value, but that value isn't the goal so much as a parameter. To be honest, I'm still not entirely clear on the mechanics. I think that some other visual metaphor, or more explicit visual language could better convey what is happening and what the goals of the player should be.