Dying Light is a first-person, free-roaming survival horror game. You're Kyle Crane, a merc dropped into the city of Harran by an organization called GRE to find data on the virus that's caused the city to be overrun with zombies. This requires you to cozy up with a band of survivors (who also saved your neck when you parachuted into disaster), and eventually a local tyrant named Rais. Over the course of the story, Crane decides he cares about the group of survivors, and becomes increasingly disgusted by Rais, and the GRE for making deals with him.
I say Crane decides he cares about the survivors, because the game is on railroad tracks as far as that goes. It isn't a matter of someone asking a question and you deciding how Crane answers or what he does. The closest you get to choice is deciding whether you want to bother with the loads of optional missions for the people of the city, ranging from scrounging around for coffee, to convincing a mentally handicapped man to let you have the medication for his now-deceased mother so it can help other people.
One way or the other, they pretty much boil down to fetch-it quests. It's just a matter of how many steps there are. Sometimes you can just go to a place, find the thing, and come back. Other times you're searching a general area, or sometimes checking multiple buildings until you find what you need. A pair of eccentric "geniuses" might need batteries from the bus station, so you've got to dodge, kill, or trick zombies until you can find buses with batteries that still have a charge.
At any rate, you're rewarded for this, and the effort of crossing the city and fighting increases your levels in those areas, which unlocks various perks that can make things easier. The ability to camouflage yourself by smearing dead zombie guts over your body, and the instant kill, surprise neck break move were godsends, especially used in conjunction. Great way to thin out a horde of zombies.
When you're crossing the city, you're relying on various parkour skills. Sprinting across rooftops, leaping from ledges, climbing vans or telephone poles to reach another vantage point. Most of the zombies are slow, shuffling types, although the person who tells Crane early on the zombies can't climb is full of shit. You very quickly encounter what I assume are former "Runners" (people who did the same jobs you're doing now), who chase you up buildings, over walls, through gaps in the fence until you can get out of their line of sight.
Overall, it's very similar to Mirror's Edge, although I found Dying Light more forgiving. I felt confident if I sprinted along a girder that I could guess when I'd reached the end and jump without accidentally running off it like a cartoon coyote. Which is not to say climbing wasn't tense. There were several times my heart rate went up, and a few where looking down or falling made me sick. One way or the other, the fact you've got Crane a long way from the ground, with very little between him and gravity, comes across.
The further along you go, the more varieties of zombies you encounter. I'm sure it's just to up the difficulty, but it feels like a sign things are going critical. More zombies are mutating into more dangerous forms, and it's only a matter of time before everyone's dead. Some like to stand on rooftops and projectile barf acid at you. Enormous hulks plod towards you with a piece of rebar with concrete around one end (including one variety that's green and wears purple pants.) At night, the worst of the worst come out. They look a lot like that one boss in Resident Evil 4, the insect thing you have to freeze and then shoot while its exoskeleton is brittle. Except there's dozens of them.
When you're just running around, you can hunker down in various safe houses, even choose to sleep the night away if you want. But some missions require you to be out at night. Your map in the upper right will show their location and which direction they're looking, and you have a "survivor sense" that will highlight important enemies and objects around you briefly if you need a more concrete perspective. I usually tried to sneak as long as I could, then run like hell once spotted. One positive, none of the Infected can swim, so if all else fails, head for the canals or the bay.
Sadly, the game insists that sometimes you not run from your problems. Though there are guns available, and even ammunition in decent supply, most combat is hand-to-hand. Weapons are often anything you can find, including part of an old gas pipe, or Old Reliable, a board with nails in it*. That said, a lot of people in Harran had machetes, sabres, billhook blades and things of that sort. This is what people resort to when there's no 2nd Amendment to guarantee their right to own as many guns as they can buy.
Weapons do wear down as you hack and clobber zombies and other humans with them, and each weapon can only be repaired so many times (and requires you have Metal Parts scrap available to repair it with.) There are also blueprints for modifications you can make. Adding a battery and coil of wire to a baseball bat so you can electrocute people as you smack them. I used those early on, but as things progressed I got out of the habit. Knowing the weapon was eventually going to be beyond repair made it seem pointless. Plus, I figured the crafting supplies were better spent on repairing weapons or making other stuff, like medkits and lockpicks.
Crane does get fatigued, so in the same way you can't simply run full speed across the city forever, you can't keep swinging your weapon like a madman forever. Eventually you have to let him catch his breath, though you can still dodge and retreat while that happens. Enemies don't necessarily show reactive damage if you target certain places - arms won't go flying because you severed one - but they do seem to die quicker if you can get them in the head than the torso, so trying to get the tiny white dot targeting reticule at the proper height can be worth the time. It isn't as simple as see enemy, hit enemy, either. Runner zombies can and will dodge and juke to avoid your swings, and Rais' men are fully capable of parrying with their own weapons. You've got to pick your spots.
Like I said, it isn't a game that lets you make decisions. Crane decides to hide his intentions from Brecken and Jade, until he doesn't. He decides when he's fed up with the GRE, he decides he's going to continue to carry out missions for Rais instead of breaking his neck the first time they meet, which would have been my preference. The guy is clearly bad news, the sort to change the terms of a deal the moment it suits him, and clearly more on the ball than Crane is giving him credit for.
So I don't know about the emotional beats. Do I share Crane's regret when he first feels he failed Jade? Not really. Would I have liked the chance, later on, to fight Jade to make her take that last vial of Antizin instead of her jabbing me? Yeah. She was apparently a mixed martial arts' legend before things went to hell. That would have been a much more interesting fight than dealing with Rais' musclebound chief goon (seen in the image above, thoroughly dead), plus the clown car's worth of nameless goons who ran in to help.
That said, one thing Crane and I were in total agreement on was Rais talks too damn much. The entire final level - at least once I got out of the sewers where I died like 12 times - Rais is on a loudspeaker, going on about the usual shit. Blah blah, Crane's just a slave, blah blah, Rais is waiting at the top, as befits a king. Blah blah, firing a missile at you is totally fair. Through it all, Crane is screaming at him to just shut the hell up, which I really appreciated.
As for the final battle, once you've finished climbing all the way to the top of this partially constructed skyscraper, I don't know how I feel about it. It's very brief, and it's all quick-time events. Rais goes to stab you, press X or die. He's swinging again, press triangle or die! While there are occasionally quick-time prompts in the game, assuming you've unlocked certain techniques, no other boss fight had been like that. Which at least grants it novelty. And you get to see him die while bragging, which is nice. Certainly more satisfying than the end of Mad Max. I guess I just really wanted to hack Rais apart myself.
On the other hand, given how much damage even his regular cannon fodder could withstand, I probably would have thrown my hands up in disgust after the 20th machete slash to the face failed to kill him.
* Note: Board with nails in it may not actually be reliable.