1. Enemy movement.
In Halo Combat Evolved and in Halo Reach we had fast moving Elites that seemed smarter because of the speed in which they maneuvered. In Halo 2 we had slower Elites, and in Halo 3 we had very slow Brutes. This affected the way in which players viewed the enemies in both of these games. In the Halo 4 campaign demo, the new enemies moved slowly or stood still while shooting. The only glimpse of intelligent movement was through teleportation and slow strafing. The game would probably be better if the slow strafing was balanced out better with faster strafing and dodging options.
2. Enemy types.
Throughout Halo 1-Reach we had a total of seventeen enemy types. The Grunts, Jackals, Drones, Skirmishers, Elites, Brutes, Hunters, Prophet of Regret, Engineers, Infection forms, Combat Forms, Carrier Forms, Tank Form, Stalker Form, Ranged Form, Sentinel, and Guardian Sentinel.
There is a possibility the flood can return since they are an extragalactic threat, and are possibly dormant on other forerunner locations, but that may be out of the question for this story arc to make the previous games seem more complete.
The Covenant seen are also a rogue group of dissidents, so many enemies like the Engineers (not really enemies), opposing Brutes, and the extinct skirmishers may not return. Currently we only know of three new enemy types, but many missing roles have yet to be filled.
3. Original Weapons
Halo 4 seems to introduce new weapons that fill already filled roles. The Scattershot is basically the flak cannon from Unreal Tournament 3, and looks like a shotgun substitute. The light rifle plays very similar to the covenant carbine. Even the reload animation is reminiscent. The DMR and BR are in the same game. While these weapons are original in design, they are similar in function. Hopefully, we will receive a few more weapons that are original in both design and function like the sword in Halo 2.
4. Call of Halo?
While the killstreaks, perks, and other additions that seem like Call of Duty are not enough to create total chaos. They do force the game out of Halo’s likeable balance. Perhaps they should separate playlists further by adding a Classic Mode with its own separate big team battle, MLG, and other playlists to keep both new and old fans interested in the game long-term.
definitely an evolution of combat! <----- lol see what i did there? XD