Custom block colors!

[Northadox]

PR3's custom block system was nice and hugely variable, but honestly it was really hard to intuit what every block does in every level with them. I think limiting customization to just the basic blocks, and having it only be visual would be a perfect compromise. I did like Jiggmin's old block skins idea where you could change their texture too, but even just changing the colors of basic blocks would be great.