No CGI and the sets are not only historically accurate, they are actually historical.
Tell me, how do you secure a historical shooting set for your low budget flick? You go to a nearest tavern/church housed in a building built a few centuries ago and you tell the owner that you are making a movie. All you have to do is to tape the lights switches over.
Furthermore, Hollywood movies usually/always draw the spectators sight to a single point/area in the shot. Let's say, an explosion, two characters battling each other, an important quest object, etc. Not here. Every pixel of (almost) every frame is important. While a main character makes a certain face, you can tell a lot more from eyes of supporting characters and so on.
All in all, movies like this have a lot to teach to all those big-budget movies out there.
