WARNING!!! First and foremost, COMPLETE THIS ACHIEVEMENT BEFORE DOWNLOADING THE DLC. Start reading the comments about 10-15 from the bottom to get the latest updates but you are better off getting this achievement before the DLC. I know this is too late for most, but comments started to state it becomes impossible once the DLC is installed the 1st time (starting in 2013). Currently the word is the patches have fixed it, but some disagree.2019 UPDATE: MULTIPLE users have now confirmed that simply deleteing the DLC and restarting the game will fix the issues. Best to delete it before you start, but if you don't, just run it through a second time.
There are 2 different ways to complete this achievement. Both ways consist of you playing all 15 levels but one is much more simple then the other. In order of least time spent.
1) Simple, Straightforward, but involves you actually having a friend. Invite a buddy into a LIVE Party. Set up a new Custom game, select level "USA - 1" then "Send out Live invites. Your friend will hop in the room with you and off you go! Beat all 15 levels in order so it is simple to keep track and know what you need to complete for the achievement.
DLC Addition: Couple of comments at the bottom of the comments. It appears the general idea is that the DLC will add to the Bugginess of the game. I would suggest completing this achievement before you download the DLC.
THE CHICKEN BUTTON: Do not use the "Chicken" button as it will not count you as completing that level FOR THE COUNTRY ACHIEVEMENTS ONLY. But per TheNutman69321: you can use chicken out as much as you want and you will still get THIS achievement. You will not however get the other four that are listed.
NOTE ON STARTING/STOPPING BETWEEN LEVELS. We had MULTIPLE times when the game would just hang after completing a level. it would normally take about 10-15 seconds for the "Advance to Next Level" button to appear, sometimes we would sit there for a minute with nothing though.
In this case, just take note of the level you just completed, back out to the main-in-game screen and set up another session. Just pick the level AFTER» the one you just completed and Invites are easy since you are in a party together. This will happen, but it won't set you back more then 5 seconds.
»Some have said that a key is to replay any level where you do not get the next level button. That the game, when it hangs, will not mark that level as completed for you. keep that in mind if you have issues but that was not the case for me
(most like the key issue in the 'bugginess' of this achievement.
This should take you roughly 1.5 hours to complete depending on all of your friend's skill.
2) Time Consuming but you don't need to know anyone...play Xbox Live Ranked Matches. This will automatically put you in a room with other player(s) and pick one level where you go head to head for the best time. Downside: You do not get to select the level. You would have to keep track of the levels you have completed plus you may have to repeat some levels before you get to all 15. Also, I imagine the MP on this will die a couple months after release.
Completing this achievement will also give you:
And as long as you can best your friend to the finish just once!