To earn this achievement, you must complete the majority of assignments and missions in the game. Missions you’ll have to complete to get to the end of the game, but assignments are optional, and are the only missable part of this achievement… and mostly only because if you ignore said assignments.
As you explore, keep an eye on your minimap for “!” icons, which indicate a mission-or-assignment sensitive object, location or character. Interact with all of them and clear out assignments as you go - you don’t need to complete anywhere near all of them for the achievements, but you should be aware of one thing: the point of no return. There are four core missions after you’re done with your first visit to the Citadel: Therum, Feros, Noveria and Virmire, listed in the order we suggest completing them. Once you’ve completed all four of these missions you’ll be funneled down the path to the endgame, which doesn’t completely prevent you from finishing outstanding assignments, but it will limit your access to the Citadel… which coincidentally is where many assignments occur. For that reason, we strongly suggest you only complete the first three core missions (Therum, Feros, Noveria), then deal with every assignment in your journal, take care of any and all possible exploration, and only after that’s all done should you finish Virmire.
A list of all the assignments in the game follows:
|UNC: Asari Writings|
|UNC: Locate Signs of Battle|
|UNC: Prothean Data Discs|
|UNC: Turian Insignias|
|UNC: Valuable Materials|