Halo 2 had to have had the hardest Legendary mode of all the Halo games. I breezed through halo 3 on legendary with the mythic difficulty skull. But Halo 2, I can remember redoing some spots literally hundreds of times.. I had the most trouble on the first campaign level on the space ship outside earth. My strategy was to always stay behind cover and be a coward and the ridiculous amount of the covenant elites with swords always chased me down.