Dying Light is a game people should add to their collections. You will get your money's worth. I finished the game with a 48 hour playtime according to the game statistics. I completed all of the side missions that I could find, but I did not complete all of the challenges though.
The game features a lengthy story and numerous side missions that net you weapons blueprints, money, and experience. There are two major maps and a couple of smaller maps. The story missions are great--multi part missions that actually take time to complete. The side missions range from fetch missions to rescuing people and other stuff. There are also locations--quarantine zones that once you find them, you have to either find a set amount of supply drops or clear out zombie nests. These are small self contained maps and can be quite challenging. I wish there were more of them. There are random encounters as well--some may be escort missions, just dialogue (providing some background about the outbreak), merchants, or rescue survivors. Additionally, supply drops appear each day that net you experience if you recover them. There are several challenges you can complete--ie checkpoint runs, rampages, etc. You also have safe houses to find and secure.
The game plays similar to Dead Island and dead Island Riptide--primarily melee focused; however you get to eventually unlock the ability to throw melee weapons. You also do get throwing weapons--shuriken, knives, and axes. Additionally you can craft specialty shuriken; mines and traps. There are also pistols, shotguns, and rifles; although the types of firearms is limited to three pistols, 1 double barreled shotgun, a semi auto rifle and auto rifle which can't be modified with blueprints. This is my only gripe with the combat system (DI-Riptide had firearms that you could modify.) The weapons follow the typical weapon color scheme of white, green, blue, purple, orange. However, there is no difference on the color of the firearms that I could see--melee makes a big difference.
The parkour takes getting used to, but it can also be upgraded in the skill tree. Once you get the hang of it, moving around is fluid and fun. I actually now like the mechanic and hope that other first person games utilize something similar.
The game features a day night cycle. In some of the previews, people were complaining that it was tied to the story. This is partially true--after the first one that is part of the story, the game then has it. Resting at a safe house will change the game from day to night or vice versa. The pacing changes dramatically during night with the difficulty rising considerably, but you receive double experience.
From a technical standpoint, the game only encountered an error and closed maybe twice while I was playing.
Overall, I would recommend this to anyone thinking about purchasing the game.