The first time you play through the game you have no idea whats around the corner. I mean like cod you know theres a terroist or ultranationalist in the next room and gears the locust are gonna pop up but with halo you gotta ask yourself what the hell is around the corner.
I mean theres just so much variety. Is it going to be elites, brutes, grunts, hunters, jackel, the flood, snipers, plasma cannons, banshees, ghost wraith, phantoms. And then theres the details like what weapons will they have or what kind of elites are we talking plain elites, invisible, sword. How many do i have the right guns. And each enemy has its own weak spot to look out for like the gun slot in a jackels shield or a hunters back. there is so much to think about i love it