The game looked and sounded great. The atmosphere was beautiful, better than any other FPSC game I have ever played. It must have taken forever to prepare all that media. The music was outstanding, how did you make it? It's professional quality. The menu was also really good. I love the idea about health in game.
There's not much that I can say that's positive that hasn't already been said by me or by someone looking at your screenshots.
So, on with the negative.
There were far too many graphical glitches in game for my tastes. There are numerous spots where there were tiny spaces between segments, allowing me to see into the skybox. There were stairs leaking through the wall, and I died while searching for the hidden area on one of the levels (forget which one, it's after the wraith guy) by crouching down and walking through a little whole under a doorway.
The FPS lagged a bit, not too much, but noticeable. This will obviously be fixed when the next update is released and Lee fixes some of the memory issues.
There were also some things I think you could improve upon.
The indoor levels as well as the last level were far too dark, I had to turn up the brightness on my monitor to see anything (and I'm usually getting yelled at for having my levels be too dark).
The environments were somewhat bland, especially in "The Keep", where only a few barrels were scattered around the environment.
The spider's texture was a bit ugly compared to it's beautiful surroundings and definitely stood out. Same thing with the barrels, they lacked the same detail as everything else in the game. If you want, I could send you a wooden barrel that I made.
The torches didn't always have lightmapping, either, such as in the level with the wraith. All I saw was ambient light, and though I could see the flames, there was no light.
Also, on the weapons (which I found very attractive and creative), you could possibly apply a specular map to them, which would make it look alot better.
Don't get me wrong, the demo is excellent, I'm just being especially hard on it because this is one of the games on here that I really am fond of, and it has a ton of potential. Hope you don't take this in a bad way.