Spirit-X

All multi-player maps:
Win six games as a Spy, six games as a UPSILON Force member, and play a total of 25 games.

Alternate endings:
Complete the indicated task during the final mission to see the corresponding ending after the bomb is disarmed.

Unlockable: Condition:
Ending A (Good) - Have NSA trust above 33% and save at least two of the three targets (cruise ship, Hisham, and Lambert).
Ending B (Normal) - Have NSA trust below 33%, and save the cruise ship, Hisham, and Lambert. Alternately, allow two of the targets be destroyed but have NSA trust above 33%.
Ending C (Bad) - Destroy all three targets. Alternately, destroy two targets and have NSA trust below 33%.

Unlockable character skins:
You have to play multiplayer to get those skins:

Unlockable: Condition:
Spy (second skin) - Achieve RECUIT level with a general average higher that 1%
Spy (third skin) - Achieve SPECIAL AGENT level with a general average higher than 45%
Uspilon Forces (second skin) - Achieve FIELD AGENT level with a general average higher than 20%
Uspilon Forces (third skin) - Achieve COMMANDER level with a general average higher than 95%

Comcast message:
In multi-player mode, select either Xbox Live or System Link. Go to Co-op Challenges, and select "CodeName: Onyx". Choose Mission 03. If you chose Xbox Live, make sure this is a private game so that you can host your own room. Press X to start the game. Go through the double doorway to the right of the gadget stock, then turn right at the stairs and walk up. On the wall will be a Comcast sign. Turn and go up the stairs once more and enter the room with the number 2 on the wall to the left of it. Once in the room, turn right to the first open window. Run all the way to the end of the walkway and jump to the landing directly in front of you. Climb up the ladder, stop, turn right until the camera is facing the building you just came from. Look up to see a huge Comcast billboard. Click the Right Analog-stick to view it from your goggles. D-pad Up zooms in, while D-pad Down zooms out.

Good ending:
as you know you need to save 2 of the 3 targets cruise ship, Hishim or Lambert. If you only wanted to save 2 of them instead of all 3 your better off killing LAMBERT as you will unbelivebly not lose ANY trust with the NSA for doing so. It would probably be better if you did kill him as it will make it easier to complete the level