I've been playing this for the last week or so, and I have mixed feelings about it, so I thought I would share.
I'll go on record as saying that aside from RE4/RE5, this is the best Zombie game ever. But that's kind of like saying you just pooped the best turd ever as 99% of all zombie games are terrible.
First I need to talk about other zombie games and why they suck.
Left4Dead:
This game sucks because it isn't even a zombie game. Sure there are zombies in it, but they don't move, behave or in many cases even look like zombies. With the brain dead hordes running at you full speed, yelling the whole time, the gigantic "tanks" and the other speciality zombies they could have called this game "Serious Sam: Zombie Edition" Also the game relies too much on guns when the whole fun of the zombie genre is melee combat. Couple that with uninteresting settings and a generic story and it just seems like a fps with zombies slapped on.
Dead Rising:
The time-based mechanic perrty much ruins this series for me. Regardless it has issues because there are several missions in the game that rely on gun usage and the over the shoulder view is terrible for aiming. Also the melee combat feels unrewarding... mash a button and your character swings away... I thought we got rid of such simplistic controls in the 16bit era. The zombies seldom feel like a threat either, with them all being a stupid, slow-moving mass. They cna much on you for ages before you die, which kind of takes the fear away from it. Also the HUMAN bosses, seem to have more stamina then the undead, which is retarded. I can shoot a zombie once and it falls, but it takes over 80 shots to kill a guy in a big-boy suit??? Oh and the weapons upgrades are trivial and add nothing to gameplay.
Random Zombie DLC for Random FPS:
They all suck. FPS are not suited to the zombie genre, because melee combat is where it's at.
Ok now for Dead Island:
The setting is great. This is the first time we play a zombie game in an open, outdoor environment. Also, like Dead Rising, it has a sandbox environment except this time you aren't boxed into a bunch of rooms and buildings. Unlike Left4Dead most of the zombies behave fairly zombie-like and have a realisitic swagger, intelligence and stamina. The combat system is fairly satisfying, despite it's flaws, and it's the first game where I felt like I was actually fighting zombies instead of shooting down random bad guys. Although combined weapons, like in Dead Rising, are fairly useless, the weapons upgrade system is fairly satisfying and none of the available weapons seem silly or worthless. In this respect, I feel it's the best zombie game to date.
With that being said, the game is still fairly terrible and has some critical flaws.
First off there's this pointless money system. You get money from doing missions or off dead bodies, when you die, you simply lose money. So far that's ok right? Well the thing is you spend money on fixing and creating weapons... weapons you build/repair by yourself from things you find lying around. So where exactly are you spending the money again? This would be excusable if the game didn't rely so heavily on you having tons of money.
You see every weapon, even ones that should NEVER break like a sledge hammer or baseball bat take damage when you use them. Hit 20 zombies with a weapon and it breaks....and it costs money to fix....and without a weapon you die...and lost money...and respawn without and money and a broken weapon in the same spot where the zombie(s) are...meaning you'll die yet again. I got stuck in this infinate loop one too many times until I finally downloaded a mod for the pc version that gives each weapon a more realisitic amount of stamina, and the game finally became fun to play.
While we are on the subject, the respawn system is almost game-breaking as well. Like a multiplayer fps, you respawn when you die, with everything still in motion (same enemies, at the same position ect...) except the respawn is at the nearest re-spawn point. What this means is you might respawn, without any weapons, right in the middle of the 12 zombies that just killed you, only to die again. The game is supposed to be single player as well, but it really isn't, unless you enjoy dieing over and over trying to kill the same enemy. Also if you are on an escort mission (UGH) and you die, your poor buddy will have to fend off the zombies while you respawn and if they respawn you too far away, they might die before you can run back and defend them.
The fighting mechanic is also flawed. Although it's the best I've seen so far, melee controls seem a little touchy (you aim like you would a gun) and often zombies will come running up and you can't hit them because they are the dreaded short zombies, and you have to look down to pop them on the head. They aren't midgets or anything either, they are just the slighty shorter zombies. Guns are also pretty ineffective on zombies, which I am ok with, but it doesn't make much sense. Guns are primarily used on human enemies though, so it's ok.
The story is utter crap. Not a bit of redeeming value to it. The characters are tired stereo-types coupled with bad voice acting and even worse dialog. You'll only see them in cut-scenes that seem completely dis-jointed from the game. They are so poorly done that in the intro video it shows "you" staggering around drunk talking to all the other characters in the game. The only problem is you are one of those characters, so at some point you are talking to yourself!!!
Also it seems that the story is crap in-game as well. You see, like many zombie games, there are "special" zombies as well, that are extra strong with special abilities. One such zombie is a gigantic prisioner in a straight jacket that looks like something out of a resident evil game. When do they introduce him? In a prision level? Nope... on the streets of the city. This sounds excusable until you learn later in the game that the prision is on it's own seperate island surrounded by landmines, meaning it would be completely impossible for these characters to appear on the main island. They do this with all of the characters at some point, essentially putting random zombies that don't match the locale all in a lump on the later stages.
With all of that I STILL suggest you check it out. It's suprisingly fun to play, and at least compared to other zombie games, it's still the best. (Again RE games excluded as they are on a whole other level)