Estimated difficulty level of the trophy - 4/10 - Great majority of trophies in Uncharted: The Lost Legacy are not too problematic and you can unlock them simply along the way while playing the game. More demanding are the trophies that require you to defeat your opponents in specific ways (e.g. killing several enemies in succession, while hidden, or by changing the attack method after each takedown), as well as the ones that have you find collectibles, of which there are many in the game. There are two trophies that are exceptionally difficult. The first one is Progress Demands Sacrifice and to obtain it, you have to complete all the stages at the highest difficulty level - Crushing. Therefore, you may be forced to multiple replays of some of the fights, before you will finally manage to kill all the enemies. The other trophy is The Way of the Warrior which has you complete the first four chapters (and the prologue) without using weapons and explosives. It is best to try to obtain this one later on, by replaying the stages at the lowest difficulty.
Number of trophies - 50 - There are 36 bronze, 11 solver, 2 gold and 1 platinum trophies to obtain.
Offline trophies - 50 - All the trophies can be obtained in the single player Story mode.
Online trophies - 0 - In Uncharted: The Lost Legacy, there is the multiplayer mode, but there are no trophies to obtain inn this mode.
Does the difficulty level affect obtaining trophies? - Yes. To obtain Progress Demands Sacrifice, you have to complete all the stages at the Crushing difficulty (if you have not chosen this level for the first instance of completing the game, you can replay stages in any order you want, because difficulty level for each one of them is checked separately).
Replay option - Present. Each of the completed chapters can be replayed, e.g. to find collectibles that you have missed, or to obtain trophies from specific activities in those chapters.
Minimum number of game completions required- one + replaying of stages. After you have completed the game, you can use the abovementioned replay function that lets you replay individual chapters. You can do that to obtain trophies that are missing from your collection.