Will Smith isn't a TERRIBLE actor, he's just slowly coming over his RARGH BIG BUFF ACTION HERO status of being loud and obnoxious. Out of all the American action stars, I generally like him the most because he has this flamboyent attitude in front of the camera... it's like other action stars try so hard to be so badass but Smith just has this cocky "i don't give a shit" attitude that fits so well.
As far as this goes, I'm probably going to be a bit biased because I read the graphic novel (the movie is based off the comic book version but takes elements from the book as well to create something somewhat original). The monsters are supposed to be vampires and Neville doesn't even get his dog until halfway through.
Still, I read interviews and such and they seem to be following the style closely. The story wasn't so much literal as it was atmospheric and Neville has like... 10 lines in the entire thing and Smith himself said "well, I don't even speak for the first hour of the film so the whole thing is about the bond between me and the atmosphere" which kind of put a smile on my face because I know someone somewhere knows what they're doing.
And yeah, 28 days later is 50 years too late
