I'm not sure why the forum didn't automatically embed that YouTube link but that CGI has aged impressively well, I've seen CGI from this year that didn't look that good.
Fun fact, it's not CG. It's stop-go animation by Ray Harryhausen. It is regarded by the man himself as the finest piece of stop-go animation he has ever done. The images on the skeletons shields are references to other creatures Harryhausen made for other movies. They are also some of the finest skeletons I've ever seen in movie/television, the only ones beating these Harryhausen skeletons being the ones in game of thrones.
on an unrelated note.