I like this app but ..... – Percolator: Dazzling Mosaics Review

I just bought this app and have been playing with it. However, I don’t see any mask feature here. I think this is just a matter of tapping and doing some adjustments but if you only want some of those adjustments or style, per se, to be on certain areas, you can’t. There’s no layers, as well, and I don’t see any tutorial, too.
Review by napereza on Percolator: Dazzling Mosaics.