I have to admit, I was a little confused the first time I played the game, but the second time I beat it, and watched all the cut-scenes and movies, I understood everything. In my opinion, it was one of the best stories I've ever seen in a videogame. The first time I didn't understand it was because I didn't bother to watch any movies because I was just too excited to finish the game.
P.S. Frozen: good advice