Halo is the story of three different perspectives : The Flood- a hive in which the all the individuals of the same spieces share the same mind (gravemind); They have no ‘self’, no individuality. The Covenant- a group of many different alien speices that participate as one entity, for one cause. Although they all have individual thought they belong to one entity. The UNSC (humans)- a single spieces with many different opinions to the war. Individualistic.
Therefore halo is an anecdote about the three different -isms of society. Collectivism (Flood), Communism/socialism (Covenant), and Capitalism/Democracy (Humans). The game shows that these three cannot exist in the same proximity as one another. This is shown by the humans attacking and being attacked by the flood and covenant. The forerunners represent the old ideals that Democracy (the humans) have forgotten and that they are trying to obtain. The forerunners are pretty much the ‘fore fathers’. So if you wanna make an amazing videogame like Halo, just rename and recreate the characters, places, and times using the storyline of WWII.
Just a funny thought i had, dont take any of this seriously. I may expand on these thoughts later though.