Hey Sir Cheese, I just played this and really enjoyed it - love me a puzzle game! I got to 2-8 before clicking off the game to do something and when I came back my controller wasn't working so I stopped as it was a bit tedious using the mouse (keyboard wasn't working either for some reason).
Only real feedback I would give is:
1) I would enjoy a few more mechanics to start to be sprinkled in like the squares where you have to go through them in a certain direction with a certain colour - I'm sure you got some stuff cooking, it was just starting to get a bit repetitive by the end and I was ready for some additional challenges.
2) I think it could do with some more palette cleansing puzzles i.e. some easier puzzles after particularly difficult ones - like it felt pretty linear in difficulty gain which can become a bit wearing in puzzles games.
Besides those two things it is pretty gosh darn awesome - definitely needs to be on Ipad as that is where I would play this.