Doug Simon offers a nicely done animated version of HP Lovecraft's classic short story "The Statement of Randolph Carter."
It's very short, and you can watch the whole thing below:
Simon et al account for the story's main arc, but they also add two other layers. We see flashbacks to the two characters working together, including a fun lobster-eating scene. There's also a parallel structure concerning the survivor's fate. Very nicely balanced.
(thanks to David Aelfric)