It's an utterly simple puzzle-action game, presented via a top-down view of several rooms in the titular mansion. You'll control a little dude named Hector as he wanders from room to room using the keys within to collect all the skull-shaped souls in each, manipulating boxes, switches, etc. to navigate past pitfalls and the mansion's skeletal denizens.
The weird thing is, I don't know why I can't stop playing the thing.
The visuals are functional (but only just), the controls (a basic keypad) are just okay, the audio is a totally homemade loop of footsteps and digitized moans that's adorably abysmal (though weirdly still kind of creepy), but for some reason, when they're all paired with the smart, simple puzzling, I found myself totally charmed.
I accept that my recommendation of PM:TRC is more a reflection on my own odd taste and inclinations than on the game's objective quality. And frankly, I'm cool with that. But give the lite version a try and see if you don't end up under its enjoyably low-rent spell.
Phantom Mansion: The Red Chamber ($1.99, Gimme5Games):
Phantom Mansion: The Red Chamber: Lite (Free, Gimme5Games):