Long time Halo fan who let go of the franchise after Bungie parted ways (it felt like the right time). I recently picked this up for the cost of a Fruit Shoot and I am kind of enjoying it.
I enjoy the sense of personal nostalgia of dipping back into Halo and I think 343 did a great job with the sound and feel of all the classic weapons. The covenant feel right too.
However, what I cannot shake is the feeling of the game lacking a narrative hook to keep you playing or the dynamism in objectives or moment to moment gameplay. Bungie's Halo effectively pioneered the "bubble" gameplay scenario of dropping you in an open map with lots of dynamic components. 343's take on that structure just feels a little empty at times. It is very subtle but I am just not feeling the pressure, the sense of survival or the feeling of just getting through the tough ordeal. It feels a little rote here or rather I don't fully feel the danger. Even the notion of a sprint button by default changes the game feel immensely and can often get you out of trouble. It just feels off or rather that Bungie just knew how to pace their gameplay and keep the moment to moment tense and engaging. Enemies here just feel like they wait around for Chief to engage.
In all, Halo 4 feels like a simulacra of an ever better game. It has all the components to be good but doesn't hit quite the heights of the series. I mentally started to opt out when Cortana exclaimed "wow cowboy" after narrowly escaping death and stopping just before a cliff edge. It just felt glib, detached and wrong; overly aware of the gamer.
And as for the Prometheans, I don't mind them for gameplay concerns, but I would have preferred them to be a distant unknown entity. Knowing about them and seeing them spoils a certain mystique of the franchise.