I'm no big brain dev, but I felt like the goo was calling to me in the comments, so here I am!
I have to say, the game's soundtrack has some BANGERS (shoutout to the credits music)! I also really liked the animation of switching between the menus in the title screen (turning the pages), it's a cool idea!
A tiiiiny nitpick would be that I think it'd be interesting to have a visual indicator/feedback of the invisible wall present around the green doors in the start of the level. When I started the game, I was slightly confused on why I couldn't walk to my left until I realized I wasn't meant to go around the door area yet. But again, just a nitpick more than anything.
It's a nice touch that you change the pitch of the sound when you Right Click, helps to make the sound less repetitive!
I have to say, the mechanic is quite interesting. Using the spells to affect the goo's speed and destructive abilities, and with actually having to draw the runes for the spells made for an interesting experience. There were definitely times in which I was drawing the Ice spell in a hurry (and failing miserably) because the HOT GOO was approaching. It was fun to see the fire spreading throughout long sections of walls really quickly. I don't even think I need to go on about how well this game fits into the theme!
At first, I was quite confused with the "Destroy" objective. I found the server room, which looked quite different from all the other rooms and thought "oh maybe this is what I'm meant to destroy", but later I understood that it was more as just a "you can destroy everything now" (which I did, I expect great pay from the Goo Council btw).
There's so many different directions this game can take, going from how different environments could get affected by spells together with the goo, to having completely new spells that affect the goo in different ways. Whatever the case, I think the idea was super cool and I feel like it has potential to be expanded in multiple ways. I enjoyed my time working for the Goo Council! Really cool game!