the sounds throughout are too sudden and end to abruptly... too isolated... needs for continuity... I understand you're going for an element of surprise, but it's a pile of noises out together essentially. listen to some other horror soundtracks and look for the organic aspects that genuinely scare you.

piano can ALWAYS be made creepy sounding, especially with some hall reverb and by panning it a bit back and forth between L and R speakers. play around