Just off the bat, I think that 4 metaphors/analogies/similes within the first 5 sentences is a bit much. Also, a spray of broken bone sounds a bit odd, as bones don't spray. Blackness doesn't drop someone into unconsciousness, someone drops into blackness via unconsciousness.

Overall, bloodstreamcity covered it pretty well I think, but I'd have to say, I enjoy your description of actions, but not the follow-up sentence/phrase that further explains the actions (have faith in your reader). For example, "She drank a bit of water from her canteen, the cool liquid trickling down her parched throat," "Gasping in air like a newborn, she breathed heavily," "His jaw, when moved, clicked at the back, and sent waves of pain roiling through his head," etc;

Only had time to read chapter 1. To be honest, Everything from lines 1-52 seemed real rough, and probably needs a bit of editing. Everything after line 52 was entertaining as hell. It was all a bit hard to imagine, my mind was straining to match descriptions and images with the actions of the characters. Maybe describe the physical setting/time setting/location a bit more throughout the first chapter? Passive voice is fine when you use it sparingly. I like to use it when my protags feel helpless and feel things "happening" to them that are out of their control. It becomes more of a device than a grammatical mode. Additionally, and this is through no fault of your own, I just felt like I've heard this all before (you did mention it was roughly based on the Last of Us). You have to throw your own voice into it, give your own texture, throw in all those important little, idiosyncratic details that make you you. If you do these things in the rest of the story, great, just make sure to do them in the first chapter two :)

I read through the first chapter without checking my phone for the time, which is more than I can say than for a lot of other first chapters. Keep it up!