It's a very good piece, better than anything i've done. With that in mind I'll give some harsh criticism of minor things, since that's probably more useful (and there are no major flaws).
The running stuff at the start. I know she's a little girl, but it really does look like she's just playing. Try get shots of her actually sprinting (or maybe that was her sprinting?). He was obviously having to just jog to let her keep ahead, which kind of took me out of it a little. Obviously an adult is going to be much faster, so maybe you could have given him a limp, so it's hard for him to keep up? Or potentially make him much further behind her, so he has to properly sprint to find her. His tripping seemed unrealistic because of the jogging. If he was sprinting to catch up, then he could trip as he gets closer to her (which would make it more convincing with more speed) and she could get then escape him.
On another acting note; I'm unsure if it's part of her character, or just one of the difficulties working with children, but that girl seems waay too composed.
The walking around the school is a little random. Visually great, but I'm unsure as to why she'd be doing that? And the final shot's of the sequence is a little unbelievable. Again visually nice, but perhaps a case of style over substance. She'd have noticed him before they're both on screen. Maybe she could've been looking around, behind her, etc, as he comes around the corner and then they both enter that frame the same way as she turns around and he approaches. I think you wanted to make it a surprise? But more tension could be created by having a few shots of him in the school too (unless you prefer the cold surprise)
The title makes it feel kind of like a zombie or fantasy movie. Unsure if you were going for that. It could simply be a case of changing the colour (unless red is significant to the film? in which case change the shade).
The ending was nice, but it seems a little odd with the guy sitting in silence on his phone. Was he taking instructions from someone? Calling a number no one was answering? It feels weird and unnatural without him talking, but I presumed it was one of those things - in which case I'd add a very quiet ringing sound effect or murmuring voice (doesn't need to be understood).
But visually it's fantastic. Editing was really nice, would be better with more fast paced acting/running - but you did as best as you could to compensate I think. Music is good, maybe a little over the top. Really dug the tone you created, and I'm checking out the kickstarter now (congrats on not just posting this as "fund my movie" - better marketing - shame the kickstarter seems to be struggling).