Esteemed scholars of expanded universe Halo lore know that the Human Covenant war was primarily a combined arms conflict. Expertly trained UNSC special forces teams carried out near suicidal decapitation attacks on Covenant military and spiritual leadership, military infrastructure, and even wiped out entire fleets before they left drydock. The Halo games rarely actually represent the Human Covenant War as the wider fiction presents it, which is why there are two moments in Halo 3: ODST that I always look back on with great fondness.
When the Covenant carrier slipspace jumps inside the city and all the ODSTs think they're dropping straight into a nuclear blast, and when the Covenant begins excavating the Ark and Buck thinks that they're about to glass the entire planet—real human moments of terror and despair that, especially with 343's interpretation of Halo and it's universe, have fallen to the wayside.
