Absolutely Fantastic.
Is it perfect? no. Is there a lot of "copy/paste"? yes. Do decisions impact the game as much as purported? No.
Why is it Fantastic? The game is a balance of action and stealth, of slow stealth and harrowing chases. The trick to loving the game is in understanding the world, the mechanics and the intent of the developers. The "copy/paste" is a bit regrettable.. visually.. but is wholly necessary in the early stages of the game. The world has fallen. There aren't standard resources. Things have been picked clean. The only readily available resources are the junk people left behind/died with, natural resources like flowers and honey. You have to learn to make do, to decide how to balance your need to complete your missions, to increase your own health/immunity and to earn the currency needed to purchase the weapons, medicines and gear needed to survive.
This can be speed-run, but its a waste of the games potential. It's best played in its entirety.. or as close as you can. Enjoy the little things.. help survivors, take on as many side missions as possible... keep an eye out for graffiti, memos and other collectables. The fun is in the hunt.. balancing risk/reward.. you're given multiple tools. one of the most useful is the binoculars. Use them whenever you catch your breath, when you're up high or simply at a new part of the city. There's lots to discover in Villedor.
What I don't like about the game.. I'm a Dying Light fanboy, but i'm not an idiot. How can Virals turn 90 degrees mid-jump to hit you? Why is the NPC dialogue "I guess it was nothing.. " after rushing in to a zombie pudding party where there's obviously been a fight. The map needs a "Hide Completed" option so we don't have to wade through a bunch of garbage icons to find the convoys, GRE anomalies, etc we're looking for. The weapon durability system is better (well.. more realistic) than Dying Light 1, but could use some tweaks.. specifically when reinforcement is applied..
Biggest peeve.. Sure.. it wasn't very realistic.. but bring back the OG grappling hook. Please.
Yeah there are some bugs.. you try righting a few million lines of code and testing every square inch of a 500sq KM world.. even with automation..
Bottom line: Dying light does an excellent job at providing what it purported to offer.. zombie killing fun in a realistic (well.. as close as a video game gets) post apocalyptic, fractured world. The weapons are fun, customizable and just powerful enough to let you enjoy some sweet kills, while not over-correcting and doing an unrealistic amount of damage.