This is a walkthrough for the Level ONI Alpha Site It is written for play on Legendary difficulty and has notes for lower difficulties. This is the second mission that you play as Dutch, with Mickey as your ally. Your mission is to defend the ONI Alpha Site facility and deny access to the Covenant. This mission is one big firefight. Your starting weapons are the Spartan Laser and the SMG. There is no subtlety or sneakiness to this level. You cannot avoid the enemy in any part of the game, so knowing your weapons, their capabilities and how to best use your NPCs is really important. There are no "good" Skulls for this mission, but Black Eye, Tilt and Mythic will make this level feel nearly impossible to beat and incredible when you do.