I hate that word, trust me. But this can hardly be described without utilising it. You made a great effort on all fronts: Scriptwriting, drawing style, animation, voiceacting. The only minor fault I could see is the inexplainability of the events (cut wire, noone there after knocking) but ultimately you did it to build up the atmosphere so that I can get over it. Otherwise no complaints.
I won't go into detail with my praise. I'll just mention two things I liked particularly:
1. Using different lineart colours like blue for instance
2. The gradation
Let me end this way - you sir are a god. Nuff said.