First of all, like with every game and especially if you're asking for feedback, I'd suggest making an
updatable link.
I love the mechanics, it really clicks with me!
I don't know why others are stuck on level 3 so much, level 5 seemed a lot harder to me, for that matter.
Level 1 is almost worse than 11, why not just start with 2?
I really liked 12, it would fit well before level 8, which I am stuck at right now.
I like how level 10 solves a bit like a rubik's cube but I hate rubik's cubes, so yeah...
Level 14 was actually alright, it just could be a little bit shorter somehow.
Other levels are pretty much fine as they are, I loved most of them and haven't completed 8, 9, 10, 13 and 15 yet.
I really hate the code, though. Mind if I rework most of it when I have nothing to do so it's simpler?
A hot-tip for level editing: I would delete characters for background1, background2 and all the "and background" in legend so there is only 1 character for a specific tile. The editor will allow you to save levels even if you don't have characters for background1 and background2, simply omitting both out of the saved level and you can use the code below to generate a new fancy background when loading a level:
[No Background1 No Background2] -> [NeedsSetup]
Right [NeedsSetup No EvenCol | No EvenCol] -> [NeedsSetup | EvenCol]
Down [NeedsSetup No EvenRow | No EvenRow] -> [NeedsSetup | EvenRow]
[NeedsSetup No EvenCol No EvenRow] -> [Background1]
[NeedsSetup No EvenCol EvenRow] -> [Background2]
[NeedsSetup EvenCol No EvenRow] -> [Background2]
[NeedsSetup EvenCol EvenRow] -> [Background1]