It took a few tries to get the hang of it but it was fun once I did. I think my biggest issues is I didn’t remember the formulas (plus the invincible enemy bug) and I never really got time to rest and and think. I didn’t really feel the metroidvania-ness, but maybe it’s because I couldn’t make it very far, but I 100% love it as a tower-defense game and definitely would play more.
I don’t think you intended it, but gamepad mostly worked, I just couldn’t use it to close the forumula.