Thanks for posting and I just watched your film all the way through. It takes guts to make a film like this and then subject it for critical feedback.
I found the plot confusing and I still not sure what actually happened. There were a number of issues with the sound which was poor in places. A good horror story builds suspense and makes you anticipate things that may or may not actually happen. Its the fear of what may happen that makes horror work for me rather than the actual pay off of the gore. The blood effect looked a little watery.
I didn't warm to any of the characters in the film therefore it didn't make me care what happened to any of them. Ten minutes is quite a long time and I felt that it unwound rather slowly, it was almost like it had been cut to maximise the ten minute limit on youtube. (if they still have that rule?)
On the positive side the camera work and lighting was fine with some nice close ups of the characters. Clearly a hell of a lot of effort has been invested in the making of the film. For only your fourth film it was a good effort. For the next one concentrate more on the sound and making me fear what is about to happen on screen.