- Estimated achievement difficulty: 5 [leaving room for the frustration variable]
- Offline: 50 
- Online: 0
- Estimated time for 1000: 15-20 hours [barring glitches]
- Minimum playthroughs: 1 [may need to replay one or two missions]
- Missable achievements: None
- Glitched achievements: 3 ["Melee Hero", "Knife Master", "Pistoleer"]
- Cheats disable achievements: No cheats
The achievements in this game are all pretty simple, although the Hard difficulty completion one can be time-consuming. With a total of twelve missions, and allowing at least one hour for each mission (a couple can easily be done in less time; several will require more), this game should take around twenty hours of gameplay to complete. The Hard difficulty also can be a little frustrating, with the enemy sometimes shooting right through your cover; but anyone who's survived CoD on Veteran should have no trouble.
Game Completion achievements (3):
The three "Game complete" achievements are stackable, so just start the game on Hard.
Accuracy achievements (36):
The trick to achieving 95% accuracy (Deadeye achievements, and also "Sharpshooter" and "Soldier" at the same time) on every level is the fact that the game allows you to save whenever you want. Simply save often, and reload if you miss a shot. Take your time shooting, unless the enemy happens to be shooting right through your cover... which is a frequent problem. The general rule in this game is: if the targeting reticule is red, you WILL hit your target; and holding LT aims at the enemy's head.
Note: the Gatling gun does count toward your accuracy-- so when you have to use it, just treat it as another gun and fire single shots and save often. I'm not certain, but I believe the cannon counts also.
Total Kills achievements (6):
The "Private" - "General" achievements come easily, as one playthrough on Hard difficulty should net at least 1000 kills. If you want to make sure you get these with no trouble, use some of the many points in the game where enemies constantly respawn (the earliest is the two cannon crews to the right of the path on the second part of Bull Run-- after destroying the cannons-- when you are told to take out the sniper), and kill until your rifle ammo runs out.
Collection achievements (2):
The photos and documents should be easy to find using this thread.
Special Kills achievements (3):
Pistoleer (100 pistol kills), Melee Hero (50 melee kills), and Knife Master (75 knife kills) are the most trouble because they are glitched. It's possible that, if you are using the "load upon miss" strategy for the accuracy achievements, the game might reset the count every time you load (I know I've personally killed hundreds by pistol without getting it). It is for these achievements that you will most likely have to replay a few missions on easy. Shiloh and Chancellorsville are the best choices for Pistoleer, since many of the enemies have pistols. Melee Hero will be fairly easy, since you can melee kill with any weapon; however, there are only a few missions where you are equipped with a knife... although the saber may count towards the Knife Master kills also (these 3 achievements are so glitched, it's hard to tell how the requirements are counted up; I got my "Melee Hero" early in the first mission after meleeing four or five guys). If you're lucky, you may be handed these achievements early; if not... good luck.