I was intrigued by the concept of Martha's Dolls - and enjoyed a lot of the mechanics at play. Who is the mysterious Martha, the doll maker? The story had a lot of interesting paths to go down, but I don't think this demo fully utilised them - I get the feeling that this is a level 2 area or a concept build more than anything else.
I liked the idea of creating a new boogeyman like Frenkie (Frankie?) and having that antagonist play psychological mind games with the main character - but the demo ended so abruptly I thought there would be more to investigate! I would certainly like to know more about these characters and the world they live in.
The knife puzzle was good - Frankie helped me out with that one ;)
A pet peeve of mine is to continuously search for batteries for a torch/flashlight/camcorder and the battery life runs down so fast here!
Otherwise an ejoyable demo, hope to see more in future.