I watched Dawn of the Dead on Saturday night, and it was decent. Not as good or as creepy as 28 Days Later, but still respectably entertaining. They managed to peg my greatest fear in the first five minutes: scary little girls (that's a great poster). Ever since The Shining ghost/zombie-girls give me chills. Go figure.
Even aside from the zombies, some parts of the movie were a bit unbelievable. How did the heroes get into the mall and why couldn't the zombies? How could the zombies move so fast without an energy source? How could the zombies be thwarted by locked doors at a mall and yet still manage to overrun a ton of army bases? How did the zombies spread across water?
28 raised most of these same problems, but the mechanism by which its zombie-ism spread were a bit more realistic and scary. Even so, no such disease could wipe out humanity, simply because in both movies zombie-ism spreads so quickly. Ebola is deadly and highly communicative, but it stays in one place because it destroys its hosts' mobility so early in the infection. Zombies can't pilot planes or ships, so it's unlikely that they could spread very easily between continents or even across deserts. Then again, do zombies breathe or drink? Who knows.
I saw a pretty cool preview of Van Helsing before the show. I hope it's good; I love vampire movies.
How did the zombies spread across water?
All your questions are good ones, but this one I think may be explained by the varying speeds at which the infection took hold. If you recall, minor bites on the arms and what-not did not "turn" victims immediately into zombies like the bites on the necks or whatever did. So it's possible that infected persons could seem normal while on boat rides or airplanes or whatever and later zombify.
This may also explain the army base question. Perhaps at first the bases were taking in "injured" persons (because initially they didn't know how the infection was spreading) and eventually the injured would turn into zombies and be on the base already.
How they got into the mall is a good question. They didn't show them entering. I recall Ving Rhames throwing a chair or something through a window, but I think that was after they were already in the mall.
When the survivors first reached the mall, the place hadn't yet been overrun by zombies. It's possible that they found an unlocked door to one of the mall stores (since early in the morning, the security guards or janitors had already arrived and might have left one open or something), and they could have easily locked it behind them after entering, preventing the future mass of zombies outside the mall from getting in.
For it's B-movie genesis and basic sci-fi silliness, I actually thought the picture was very well done, intelligent in spots even. The choices of Muzak were brilliant and little in-jokes most moviegoers probably wouldn't get.
When the party first enters the mall, the Muzak is "Don't Worry, Be Happy." When Mekhi Phifer is checking the doors, the Muzak is "All By Myself."
I thought those and others were good touches for ostensibly a popcorn horror movie.
Jared: Good point about the army bases. I agree as far as the general quality goes. The film was pretty fun to watch.