If Legendary is too easy for you, use the Assassins skull to activate the most challenging way to play Halo 2.
This skull is located in the "Pass through the submerged structures" portion of the Regret level. To activate this skull, you will need to play through the level on the Legendary setting. Once activated, the skull will cause the notification text "Assassins" to appear. The effect of the Assassins skull is that all enemies have permanent Active Camouflage (see Figure 2-24; note that the Blind skull [Hack #8] is also active; therefore, there is no visible HUD).
This skull is for those Halo 2 gamers out there who feel that Legendary mode is just too easy. Personally, I can't imagine anything worse than invisible sniper Jackals.
This hack gets a medium rating because you will need to play through a lot of the level to get to the skull. In addition, this skull requires that you defeat a considerable number of Jackal snipers. For this reason, I suggest that you first retrieve the Envy skull [Hack #13] . When I first went for this skull, I had Grunt Birthday Party skull [Hack #11] active. I thought that it would help me get through the Covenant in no time. However, there are quite a few Jackal snipers on this level. The problem with snipers is not killing them; they are relatively weak. The key is to see them before they see you. For this reason, Active Camouflage is invaluable on the Regret level.
Figure 2-24. The Assassins skull ...