After beating the game in single player, and with my roommate in co-op lan, I have some minor observations.
For one thing the interface is fucking clunky. Sometimes navigating the menus is more difficult then playing the actual game.
Weapon durability blows. It always has blown, and it always will blow. nothing is more flat out ridiculous when you start out, have 12 variants of ye olde wooden stick, and they all end up breaking in the middle of a fight, surrounding you with 12 infected which tend to run a little bit faster then you can.
Moving is like driving a tank. Which is ridiculous considering you're on foot. And then oddly the driving is done fairly well. Until you get the tank. Half the time I can't see out of that thing. There may be a button to get a third person view on the vehicles. I'm not sure. I still have a bad habit of running into shit. Although i'll admit that i'm not the best at any driving be it RL or in game.
The weapon selection is invariably poor. As aforementioned, in the beginning I found myself running around with 12-15 variants of a broomstick. You can get "Recipies" to upgrade these weapons but none of the good ones really pop up until much later in the game, and even then they're not that great of upgrades. (I found the shock based ones worked the best) I realize they wanted to make it somewhat realistic, but no. It's a zombie game. I don't want to know how well i'd actually do in a real life zombie based combat situation. I want to believe that with nothing but a Katana and a Handgun i'd be invincible.
Recipies are Bullshit : In Dead Rising 2 (The game this game gets invariably compared to) When you combine cool shit, to make even cooler shit, (With the handyman's secret weapon no less) you can fuck around and pull shit out of your ass, without earning any of the trading cards that show you how to do it. Which gives a bit more of a "Surprise" feature to it, plus you don't have to hunt for all the cool shit. For half the game I had all of the shit to make shock based bladed weapons, but I couldn't actually do so until I had already found a katana or two.
Guns are boring as shit. There's roughly your 4 types, Pistols / Shotguns / Semi Auto/Burst Rifles / Full Auto Rifles. Each one gets itself a subcatagory of "Types" but the differences aren't really all that great, and I find them relatively useless, especially considering how little ammo there is.
All in all, save your money folks. If you really want to play dead island, just play Borderlands again and pretend the enemies are zombies. you'll most likely have more fun with that.