Dead Island really could have been handled a different way. Think of the resort's advertisements: "We'll murder your troubles! We'll slay your stress! We'll demolish your dreariness and revitalize your relaxation!" What's that, you say? You like fighting off zombies during your vacation? Suit yourself. 

We took some time with Dead Island and learned a little more about its multiplayer mode. Dana Vinson enlightens the masses:

The entire campaign is playable in co-op mode, and you can drop in and drop out with different friends at different times, or play consistently with the same people to level up together. If you choose to play with someone who’s a higher level than you, the game will warn that there are spoilers ahead. At that point, you can choose to proceed or not at your own mental risk. If you hate people and want to play alone (or maybe you only sort of like people so you have a team of two), you will not be accompanied by AI teammates; instead, the enemies will scale depending on the number of players in your party.

That sounds like some intelligent game design to me and it looks like the developers have put the same amount of care into sculpting the title as a whole, but don't take my word for it; check out our Dead Island E3 2011 Multiplayer Preview.