I played a couple hours of this a few years ago and was forced to stop because my PC broke. It's a metroidvania style game with a tomb/underground labyrinth theme instead of Sci-Fi or Gothic. The game is very large and difficult in comparison to either Metroid or the later Castlevania games, with a heavier emphasis on puzzle solving.
One example of the higher level of difficulty that comes to mind is the leveling system. Unlike Castlevania where leveling actually makes your character stronger, in La Mulana you will find yourself fighting for some hard earned experience points, only to realize that "leveling up" simply refills your health bar--no stat benefit whatsoever.
Graphics might not look like much from the screenshots but there is some quality to them. I don't think the game reuses many assets at all, and some of the larger objects are quite detailed.
Again, most of these comments are from distant memory. I first heard about this game from the ABDN review (it's a good article, not so much a review):
http://www.actionbutton.net/?p=193
http://agtp.romhack.net/project.php?id=lamulana - Download + English Patch.



