I feel like the MC is just such a Mary sue. She aint supposed to know about military tactics. She's just supposed to be skilled in medical treatment, and have some pre-knowledge of the world. She's also an extremely good shot, which is really weird.
Also, the technology of the world is all over the place. At first impression it feels like medieval times, no technology and shit medical treatments. Then BAM we're in the 18th century with guns and all that, and fat ass magnum revolvers... Then suddenly we see modern guns with clips, and teleporting princes that has no such ability?