la-mulana is a very mean game, but it's not really mean in the way I think someone trained on modern metagamey-games might expect. It's not going to delete your save file or lock you out of a good ending or something. It's not going to make you lose hours of progress. It's going to kill you a bunch in capricious ways but that's not really the mean part of it.
The part of La-Mulana that's mean is that it has carefully designed all of its puzzles to be a just-so level of maddeningly vague such that you can, and will, eventually hit one that causes you to spend hours trying the wrong things and making absolutely no progress until you're ready to tear your hair out. It's the things that la-mulana does to you psychologically where its cruelty manifests.
(great game tho)