This list is to show the unlocks go in each specialization
- 1st Set of Armor - Reach specialization ranks 2-4 to unlock the entire 1st set
- 2nd Set of Armor - Reach specialization ranks 7-9 to unlock the entire 2nd set
- Specialization Package Mod - Reach specialization rank 10
- Specialization Visor - Reach specialization rank 6
- Weapon with Alternate Skin - Reach specialization rank 5
Legendary Completion Unlockables
After completing the Campaign on Legendary, Single Player or Co-op, you will unlock a few features to be used in Infinity.
- "117" Emblem - Beat the Campaign on Legendary
- Legendary Visor - Beat the Campaign on Legendary
- Mark VI Armor - Beat the Campaign on Legendary
- Knight Helmet - Unlock the "Knight in White Assassination" achievement to earn this award.
- Platinum Mark VI Helmet - Unlock the "Wake Up, John" achievement to earn this award.
- UNSC Infinity Hoodie - Unlock the "Not Some Recruit Anymore" achievement to earn this award.
Conan and Andy as NPCs
Near the start of Mission 6, you can find NPC soldiers who were voiced by Conan O'Brien and Andy Richter as part of a promotion on "Conan." Head to the lower part of the hangar and you'll find the two soldiers standing in the corner. Wait for awhile and they'll start conversing, which is when you hear the special dialog (the video below shows it in action). There are three separate conversations that you can hear before things start repeating.
Red vs. Blue
Play the Spartan Ops campaign and work your way through Chapter 5 of Episode 1. As you near the end, high on a bridge, you can stand on a railing and shoot down at a hidden object to earn an Achievement and hear a recording of the Red vs. Blue easter egg (see the video below for the exact location).