I'll join in and say that this movie was easily better than some of it's predecessors, but if I'm going to be honest that's kinda like saying that getting kicked in the head is better than getting kicked in the testicles.
First off, the opening 15 minutes is stupid as hell. It's completely impossible to take any of it seriously and it's not even fun, it's just painful to watch. The action isn't just over the top it's cartoonish. And you had damn well better hope you remember the previous movie or the army of Jovoviches comes off as a big blue light special of extra strength stupid.
Easily my favorite part of the opening sequence is right after Wesker reveals that the T-virus turns your blood into a bowl of Mr. T cereal and then suddenly remembers he's supposed to have been flying the plane.
"Hmmm maybe I should stop monologuing and get back to flying the plane before we crash into a mountain...whoops too late."
After that series of Wile E. Coyote style action shots the movie does get better, after a poorly explained but alltogether welcome bit of backtracking they make sure that Alice isn't the queen goddess of all creation anymore and she's just a regular old bad-ass chick with a lot of guns.
Unfortunately now that all the flashing lights and electronic bass beats have stopped you're able to focus on the laundry list of plot holes that the movie presents.
What ultimate goal is to be served by destroying all of civilization and turning them into mutant zombies?
Does Umbrella even have a plan or are they just a generically evil organization like COBRA from the GI Joe cartoons?
Why didn't Chris have a military ID or some sort of documentation he could show in order to prove his story?
Where did this second strain of zombies come from?
What's up with the Axe man, where did he come from, why does he look like a DIY Cenobite?
Why was there a boat in the sewers?
There's this little trick that the big boy storytellers like to do called "foreshadowing" this is when you mention something, or drop hints into the story about plot points or characters which may become important later."
This helps to avoids confusion when you eventually introduce that plot element into your story. As I mentioned earlier, the movie doesn't do a very good job of explaining plot points from the earlier movies and as a result you're just left in the dust if you don't remember.
Who is K-Mart? Why is she named after a department store? I know she was in the last movie but clearly she didn't leave an impression, so why should I care?
This is doubly problematic during the big surprise character reveal.
It's been almost 7 years since the last time the audience saw that character, don't just dump them into the movie looking nothing like we remember and expect people to get it. I'm not saying the plot had to revolve around it but throw us a bone here. We just spent the last 80 minutes or so watching Alice and her pals escape from a prison, our minds were not focused on the plots and characters from the earlier installments of the series.
Lastly.
There is WAY too much of the slow-motion-fade-into-action trick in this movie.
I think I can say, without threat of hyperbole that the movie would have been a good 10 minutes shorter without all the pointless slow motion shots.
I think in the end it all boils down to this.
If all you want is to see some folks punch, kick and shoot zombies for a few hours then you may enjoy it.
But if you want anything else, you might want to just go watch Dawn of the dead again.