theatrical trailer is th ebest i've ever seen for any game.... but i havent seen any gameplay 
there have been some gameplay vids on xbox dashboard. Imagine it as a cross between fallout and left 4 dead, free-roaming RPG style FPS with 4 player co-op.
http://www.youtube.com/watch?v=pVzRo39P31I
from what I've read it's more L4D than fallout and pretty much just an L4D clone that switches the focus to melee attack, I wont be buying.
...except L4D is linear (i.e. get from point A to point B without dying) whereas Fallout & Dead Island have open-world environments and are more missons based, use an XP system for levelling up etc...
Not that there's anything wrong with L4D (I love the first one, not too keen on L4D2). However all the Dead Island gameplay vids i've seen look very little like L4D.
