Claire Refield, Leon Kennedy, and Ingrid Hunnigan are the only characters that come from the video game series, and voiced by the same actors.
(at around 23 mins) The scene in which Claire and Leon meet, is a reenactment of how they met in Resident Evil 2 (1998). In the game: Leon runs towards the diner and sees Claire being faced off with a zombie. He say's "Get down!" and shoots the zombie. Claire then looks at his face as he offers her his hand. In the movie, Claire goes off to look for a survivor that she hears running around, she looks out the corner of a wall to hear Leon say, "Get down!" He shoots the zombies and offers Claire his hand as she says, "Leon!"
(at around 23 mins) The umbrella Claire Redfield takes as a weapon when exiting the VIP Lounge is colored the same way as the Umbrella Corp logo. Claire even jokes about this during this scene.
This the first Resident Evil movie to be in CGs (computer graphics), and is also the first Resident Evil to be based directly off the games, and not an original script like the live-action movies were.