As Prelude clearly states in his review, there are tons of plot holes, from start to finish. He's mentioned the most important ones.
My problem with this film is also with the idea - it's such a simple plot: allegedly there is one last man in NYC after a virus wipes out everyone else; he's a doctor and wants to save the world by finding a cure to the virus.
The way the plot was handled could have been better, there were so many opportunities for it to sway, but there were no surprises, just the typical Hollywood trash.
As for the acting, I can't say Will Smith impressed me. Not a noteworthy performance.
I did like the fact that there weren't many actors, and that he does go nuts (clearly visible in the video store scenes) because he lacks a social environment.
Also, I found the Dark Seekers to be terribly badly done!!!! What a crappy CGI.
Hollywood-movie lovers, watch it, it's action-packed. If you're looking for some decent script and good acting, this was pretty lame, so stay away.
4/10