This is a good short-film. It contains the necessary "ingredients" that are required to make a suspense, thriller, or horror movie. I found it in the thriller category at ITunes, but it could go in horror, too. Anyways, whether it's thriller or horror doesn't matter because it's sure enough scary. The main ingredient that makes any movie of any genre a good one is the music, and the music in Hollow is timed perfectly to make anybody jump, and then, other times, it's just right to give you goosebumps and make you wonder what's coming in the next scene. Next, the lighting is done well, although at times I thought it might have been a little dark, but I soon realized the darkness was appropriate for the scene. The actors all do very well. Caulfield won an award for her role, Crawford did well in his supporting role, and Israel did very well in a role that I think challenges for the lead.
One slightly obscure part to the plot is the undeveloped storyline for the red door and for the scene in the dining room. However, the suspense around the door is a major factor in the movie. I'd just like for a good scary storyline to be written and made into a full-length movie. All in all, this is just a plain 'ole good scary film. No CGI, high-action effects or heavy gore. It's just good and scary. Similar in ways to full-length psychological thrillers like "Jacobs Ladder", "The Ring", etc.