A tutorial would have 100% improved it, I agree. As a team of programmers, I think we focused too much on making the mechanics cool instead of easy to understand.
I also agree that finding things in the level is very hard and not clear enough, given the time I would have liked to add helper arrows that point to the next objective.
In fact, the "Destroy" objective isn't really an objective, just something you are being told to do! I think that was poorly communicated.
To interact with the goo, you have to cast spells on it by opening the canvas with right click and drawing the spell you want on it. Heating it up makes it spread faster and destroy things, cooling it down makes it slow and makes it more safe. The main idea of the game is to destroy the level until you find the schematics, then to leave the level.
I can't comment too much on the rune drawing mechanics as that was Nijelous who did that, but we wanted to try and make it quite lenient with the shapes since we only have two spells anyway.
Thanks for playing!