...that the Covenant produced an AI capable of thinking for itself and betraying its masters?
...that the Unggoy Rebellion began as a conflict between the Unggoy and Kig-Yar over shared resources?
...that slipstream space translations for a Phoenix-class colony ship require 4.3 quadrillion (4.3 * 1015) calculations of the quantum field per second?
...that a Flamethrower was intended to be put into the first two Halo games, but for balance reasons wasn't included in campaign until Halo 3?