Hi - thank you very much for your time playing our game, feedback and kind words. I'm extremely excited and happy to see people enjoying the game.
Since submission, we've been thinking about the same adjustments to manipulating the brushes as well - especially with mouse input.
In retrospect, a few of the ways I went about implementing the selection (and when it declares you in an invalid position for that face) can be cleaned up a lot, and it's my first priority in the future upon return after the voting period.