You can't say “Dead Islands” doesn't have action. From the opening scene in the streets of Shanghai, to a zombie attack in an airplane over the Pacific, to utter chaos in the Hawaiian Islands, “Dead Islands” keeps moving throughout.
Curiously, no one in the early part of the novel seems to be aware of the spate of zombie movies flooding the theaters these days. Everyone's like, “I never heard of such a thing.” That doesn't make the book bad, it just seems odd to me.
On the other hand, once the heroes land in Honolulu and get through the authorities, they kinda brush off the whole thing. They act as if tangling with zombies on airplanes is just an interruption of their mountain-climbing.
One of the toughest things to write believably is how normal people will react to abnormal, bizarre, or horrifying situations. Do they freak out? Do they shrug it off? The characters here seem to take it mostly in stride, considering how bizarre the situation is.
On thing that's nice, “Dead Islands” is set slightly into the future and makes reference to very recent events like the Russian involvement in the Crimea and Wikileaks. That gives it an up-to-the-minute feel, connecting real-world events to the horror of flesh-eating zombies.
However, I do not like the ending. Actually, it ends fine... except there's an extra chapter, set in Washington DC, tacked on after it! Though this chapter relates to the zombie apocalypse, it shows us new, unrelated characters. Even this might be OK if it had been labeled as a teaser or an epilog, but not another chapter. Still, it's not enough to ruin the good experience of reading “Dead Islands”.