It doesn't win many points for style or finesse, but Dead Island packs in more than its share of fun to compensate.
+ Fun, fresh, and ridiculous melee combat
+ Great atmosphere
+ Works as either a solo or co-op with friends experience
- Poor story and character development
- Uninspired side quests
- Missing some polish; occasional bugs and design quirks
It's easy to frame any zombie game experience in terms of Valve's Left 4 Dead series, but Dead Island has more in common with Borderlands (lots of loot and great co-op) and The Chronicles of Riddick: Escape From Butcher Bay (intense melee combat with tons of "oh-snap" moments) than anything else. It's an open-world zombie obliteration simulator, and in that regard, it succeeds admirably. It's got some rough edges, both technically and design-wise, but the core mechanic of brutally slaughtering your zombie foes is borderline perfect, so it's easy to forgive Dead Island's faults.
While you can play the game withe either "digital" or "analog" controls, the definitive experience calls for analog controls, which lets you use the right analog stick to swing your weapons about freely (note that if playing on the PC, you'll need to use a controller to use the analog mode). The combat has a lot going for it: every weapon has its own timing and range to it (as well as RPG-style item stats), and there's nothing more satisfying then slamming a perfectly-timed nail-studded baseball bat into the head of a charging zombie. Having put 40 hours into Dead Island over two different characters (one specializing in blunt weapons, and the other in sharp weapons), I can say that the combat still feels fresh and exciting and that every weapon has its own unique feel to it. Even the shooting sections, which are a bit clunky with a controller, are fun and well paced, and include lots of well-placed cover that turn these sections into something you'd see in a police movie shootout.
And it's a damn good thing that the combat holds up, because other aspects of Dead Island don't. While the four playable characters are given a good introduction, there is absolutely zero character development. The plot is serviceable but usually aimless. The difficulty can swing dramatically from being a tad easy to incredibly difficult (although I guess this makes it perfect on average). Many of the side quests are uninspired fetch quests. However, none of these issues really detract from the overall experience in a major way. Sure, you're on fetch quest number 21, but you get to plow through hordes of zombies on the way, and that's guaranteed enjoyment right there!
Aside from an open-world and color coded-loot, Dead Island also resembles Borderlands in that it features co-op for up to four players. However, Dead Island is a much more fully developed single-player experience than Borderlands. Playing solo allows you to really soak in the incredible atmosphere, while playing co-op can make for interesting team dynamics and a chance to try a different playstyle (of the four characters, the two melee specialists seem best suited for solo play). Dead Island features a system that allows you to instantly join games of people playing online that are physically near your location in-game, but much like Borderlands, this is a game better played with friends than with strangers.
This is a Techland game, so there some bugs here and there, but they aren't terribly common and really only stand out because the rest of the game is so engaging that it can be a bit of an experience buster to see a floating object or a tear in a texture.
All told, you will have fun playing Dead Island either alone or with friends, provided you go with the analog controls. It's a great start to what we can only hope will become a more polished and fully-realized series of games. With a lot of content that stays fresh with time, picking up Dead Island is an easy recommendation to make.