This is actually an interesting concept and a great theme, however they destroyed it all by using poor acting and even worse dialogue.
I have always been a big fan of movies with demons, angels and the like and taking the Frankenstein story to this theme is really a good idea. Most of the story and most of the things behind it are quite interesting, but there are some points that are a bit over the top and I think that is a bit of a shame. The theme is basically good vs evil and the war between angels and demons obviously results in an epic battle between the two. However it does seems a bit silly that a human construct like Frankenstein's monster is actually a central key element in resolving this whole conflict.
The special effects are really good. The way the demons explode, transformation of the angels and gargoyles etc. is well done. The somber gothic theme is just brilliantly applied to almost everything. It is very well done and that in itself maybe makes the movie worth seeing.
In general the acting is pretty poor but there is no performance worth pointing out here. At several points the dialogue becomes so awkward that they might as well have used cardboard figures.
The movie is worth seeing if you are into this dark gothic summer theme and though some of the parts are pretty lame it is still a very interesting story and concept. I am primarily ranking this movie low due to the poor acting and the flawed plot in an interesting story.