Distancing itself from the games is basically a must as the game suffers from the common curse of successful series (deserved or not) of there being too many spinoffs and sequels for the story, so they had to invent several more universe threatening enemies that only the main character can stop. How many of those did Halo had by now? 3?
And now they are basically back at square one with the story only that they changed out the main alien race they are fighting.
And now they are basically back at square one with the story only that they changed out the main alien race they are fighting.