A rescue mission, that isn't all that it seems... |
Two of the trophies on offer require you to perform specific tasks within the DLC storyline. The"Last Stand" trophy, which requires you to complete all 5 waves in the battle for object Roh, is probably the harder of the two, but that doesn't exactly say much, it's just the one most people will probably need a few attempts at trying to achieve, if not done in one shot.
Even if you do struggle on either, simply reloading the last checkpoint will take you to the beginning of each relevant point, you just need to be aware at when you're actually at the point in the story-arc where the trophies can be achieved, and not skipped over.
You also get awarded "The Ultimate Sacrifice" trophy, for beating the Arrival DLC, which takes no longer than 1-2 hours, depending on how long it takes you to get the other 2 trophies, which are missable, but easy enough to keep track of and unlock, to not require multiple play-throughs at the same time.