It's important to know that the game was released literally unfinished, it's because Ubisoft hand this game over another game studio, which (I guess) released the game in condition the original developers left this game shortly before Ubisoft took it from them.
It expains everything that can be wrong in this game, especially it explains very well why the "ending" of this game is so dull; the game just ends in halfway of story, leaving a player with accidental cliffhanger that doesn't explain ANYTHING, in moment when player expects a climax of story. And protagonist doesn't even searched for his family in game (only in first 30 minutes) and whole game he's helping another family which he knows only a couple of days!
But atmosphere and parkour mechanic is great. It's frightening to climb on skyscraper and other tall buildings because you have limited stamina and you need to take a break or you may fall to death. Whole concept of lethal dust is pretty cool.
Combat mechanic is kind of realistic, people are scared when you point a gun on them, though if you don't shoot for too long, they can realise you don't have ammo. It's very cool concept I wish the game did better than it have right now. Combat becomes very monotonous after half of game as there is always one tactic for all battles. And when you get a bow with one arrow, which can be used infinitely, you don't longer worry about ammo until the end.
The game is trying to create an illusion of scarce resources, but very quickly you will get a lot of items restoring health and stamina and you just stop caring for them
I Am Alive had a lot of potential which was ruined by Ubisoft, and it's very sad, as I liked this game on first walkthrough. It's better watch the game on youtube instead of playing it if you want to try it, because of game's unfinished status.