Overall the idea is on point. Hit the money on it, could be something huge. A good demo for H-Content, but the RPGmaker elements are a bit iffy. The puzzle is not exactly the best, since there's nothing on the first floor. Maybe move the camcorder scenes down there and remove one or two more trunks? The second floor can have other things in it down the line, like bullets or one of the tickets.
Walking through the city is well, a pain. I see what you're going for, and I like it, it's just it doesn't work since the buildings just block the view for the player. Not too much of a problem since it's a walk section and no actual importance can be found other than the tickets and setting the scene.
One other thing to think about is the section where you hunker down with Heather. Come on, you just saw a bunch of monsters appear out of the blue, at least arm yourselves and barricade up before indulging in some heartfelt moments. Get what I mean?
I'll give this a solid 7/10. You've got something good here, just need more time to work and polish it up.