Adventures of Shuggy (Smudged Cat Games)
"Shuggy has just inherited a castle full of goblins, ghouls, zombies, and robots. Help him clear out over 100 rooms to make his new home liveable again!" - Author's description
note: The Adventures of Shuggy have finally (and just) been released for Mac and Linux. That's why a 2012 is being mentioned again. Also, it's quite the indie classic.
Purchase the Adventures of Shuggy on Steam (Windows, Mac, Linux)
Purchase the Adventures of Shuggy via Smudged Cat's site (Windows, Mac, Linux)