This was a fun read, think I got all the ends. It never seems like it's quite possible to fully grasp what's going on, and the metaphorical "door" and "thingie" are always sort of floating there. The horror here I think is half in the body horror, but half in the inability of the reader to get a concrete foothold. It's a neat effect.
The surrealistic and (at times) vivid illustrations helped the atmosphere. Maybellene's goofy sprites are all fantastic.
The script could use some cleanup here and there for typos or to remove the stuff that sounds like stage directions (converting A WHILE LATER into a fade, for instance) but then again some of the disjointedness of the story comes down to disjointedness in the script, and it might not have the same feel.