I really like the analysis tool on chess.com that processes your games and identifies the Excellent and Good moves, as well as Mistakes and Blunders. It also proposes which move should have been played.
I realize it's probably based on a drop or increase in your piece advantage, but I really like this tool since I can clearly see what were my opponent's blunders or mistakes (as well as mine).
Is there an Android app that has similar features? The chess.com app allows me to analyse my chess.com games, but not to import a PNG and process it. Other analysis apps I've seen only return the "piece advantage score".