-Estimated achievement difficulty: 4.5/10
-Offline: 46/46 (1000)
-Approximate amount of time to 1000: 15-25 Hours
-Minimum number of playthroughs needed: 2
-Number of missable achievements: None (Mission select)
-Do cheat codes disable achievements?: No cheats
-Does difficulty affect achievements?: Yes, 2 achievements ('Look mom, I made it!' and 'Just a scratch')
-Glitchy achievements: None
-Unobtainable achievements: None
-Extra equipment needed?: None
Welcome to Army of TWO: The Devil's Cartel! The third installment of the franchise, see's you take control of different characters this time around, abandoning Rios and Salem, in favor of 'Alpha' and 'Bravo'.
The achievements are relatively straight forward and you will likely obtain a majority without going too far out of your way. There is only 1 achievement where you will need to be online, which is 'TWO heads', (Complete a mission (excluding New Blood) with a human partner), as the other achievements for Co-Op related activities can be earned with the AI partner. Although it would be a good idea to attempt these with an actual partner as you can then control the situation.
Step 1 - Campaign, Casual/Co-Op
Your first step, naturally, would be to play through the campaign. You can choose to do this with a friend, over Xbox LIVE, but you don't need to as you can earn all of the achievements on your own. The majority of the secret achievements are story related and are thus unmissable, so you will unlock them as you complete missions or the game.
While you play through the campaign for the first time, you should be conscious of the miscellaneous achievements that you can earn along the way. It is recommended that you attempt as many of the miscellaneous achievements on your casual playthrough as possible, to minimize the difficulty in obtaining them.
Step 2 - Campaign, Insane
After you have completed the game once, you can then begin the process again, but on Insane difficulty. The achievement you earn for doing this, will likely be the most difficult in the game, so take your time and play with a friend, if you feel that would make the playthrough more manageable.
You can only play on Insane difficulty after you have completed the game at least once on a lower difficulty.
Step 3 - Miscellaneous/ Clean up
After you have finished the game on Insane difficulty, the achievements you will likely have left will be, to purchase all of the purchasable items and possibly some of the 'Kill x enemies' achievements. You will get money for completing missions, so finding a well paying, but short mission, will be the more efficient way of amassing enough money to purchase everything.
As for the 'Kill x enemies' achievements, you can find an area, with a heavy enemy presence and attempt these there for the best chances of obtaining them.
So, although not very easy, the achievements are straight forward. You can complete everything with a friend as your Co-Op partner, if you so choose, but you only really need a human controlled AI for 1 achievement.
[x360a would like to thank Scotty for this Roadmap]