Sorry to have taken a little while to get back to you, spec_x.
First off, the good stuff. Kudos on a brilliantly optimised terrain. This map runs silky smooth with very little in the way of dips in fps on a wide range of systems all the way down to minimum spec, and this is a great accomplishment. I'm sure it helps having that large mound in the middle!
The custom static meshes for the lanterns are also nicely done, but some more on them shortly. The custom music track is great and works well with what you have done so far.
Now for some thoughts!
I can see the type of theme you're going for, a kind of deserted and haunted place (hence the name!) where blood is still fresh, however, to be honest the blood pools still don't do it for me. They don't look that cool anyhow, and despite the bloodstains in the snow to support them, they don't quite convey a sense of doom, to me at least. Having seen them in-game, I still think custom enviroment maps would pull more eye candy without sacrificing your intended theme. The static meshes for the lanterns aren't convincing as light sources in their current form. The fact that you can see into the cone where there is nothing creating the light is the issue here. I would suggest placing a corona light inside the cone so that as players approach they at least see something shining.
Despite the level being brighter in-game than in the screenshots, I think it is still too dark. I'd suggest increasing the size of the moon in your skybox. As it is it seems a little small. It may be realistic in size, but that's for here on Earth, and we are playing Unreal so you have some license with things like that. I'd make the moon 2.5 to three times as big, and then you could increase the brightness of your sunlight actor giving the entire level greater brightness but in a believable fashion (because the moon is so much bigger).
The cabin. Yes. Perhaps you have plans to add further detail? I'm thinking that you would be better having the place boarded up, with some flickering lights inside but players unable to investigate further. It raises questions in the players' minds like "what's making that light in there?", adding to the mystery. Besides, the interior is very cramped and shouldn't become part of the play area. It looks bland inside now and adding detail is unlikely to help enough to make it worth the effort. Think about adding some glass windows that are frosted over to obscure vision into the interior. If you're game, you could even play with an alpha-channel texture to allow players to see shapes inside with being able to really make them out.
Continuing on the architectural note, whilst I see what you're trying with the broken walls, they really look rather tacked on and unconvincing. This also leads to the bain of many terrain based levels. Despite your efforts, I still feel that the level lacks a real personality. The existing architecture is just too insufficient to establish an identity or develop a theme. I think the level would benefit from a substantial increase in architecture of some form or another, because depite your efforts it still feels rather bland and without its own character. Those lanterns are a step in the right direction. Perhaps you could take their design style and attempt to apply it to more broken ruins that are more substantial than the token walls you currently have scattered about. You would also do well to attempt to vary lighting, texturing and/or mesh work throughout the level to enable players to differentiate between various areas. The entire level feels to consistent to enable players to navigate effectively.
These are just some thoughts, of course. You have a good beginning, but there is some work ahead if you want to lift it above the sea of similar levels.