Wow, thanks for the super detailed and nice comment! 102 is an absolute wonderful score , top tier. My record is 108, but my next best is 101!
I completely agree with you:
-I never considered adding an undo but it could make sense (once a new layer is added you can no longer undo past that moment seams like a reasonable rule).
-The game is indeed monotonous once mastered. It may take 20-30 runs to make consistenly more than 90 points, but after the game rarely offers new situations.
-New rows consist of fire, water, mud and grass, and a 1/5 chance to delete any of those tiles. Maybe having different random rules for every couple of rows could create some flow in the levels, what if you had rows with 2 or more fires? What if there was a row filled with mud? This might make the game less monotonous too.
I don't think I'll update Layers soon because of other projects, but just reconsidering the design is a very nice excercise, so thank you for your thoughts!