Are the sound effects in game? The thought behind this is good, the timing for the scary moments could have been better. Alot of the reason the zombie scene was "Cheesy" is because of your lack of filming skills, for instance you focused the camera on the bodies, which gave the fact that something was about to happen obvious. A better way to perform that would have been to focus on something else in the room, perhaps an alter with a letter on it. After reading the letter then the zombies would make themselves known.
Hope I helped some.