The problem with video-game movies is that their structure is entirely different. Video games, as a rule, cannot be squeezed into the general three-act structure of movies. It just isn't possible, things are going to be left out. Not due to time constraints, but due to writing and plot flow. You couldn't make a movie about FF7 and have *all* the party's adventures to like, Corel and Rocket Town and Wutai, etc. You just can't, you'd have to abridge it. But even with the core plot elements - meet Aerith, escape Midgar, Nibelheim flashback, Temple of the Ancient, Forgotten City, North Crater, Weapon, Huge Materia, Midgar revisited, North Crater. See, even then, way too much to compress into one film. You could snip out the Weapon-Huge-Materia-Midgar revisisted stuff and have the final battle take place during the first visit to the crater, but it's still a lot to compress into one film and make it good.
A direct movie adaptation of a video game is thus impossible, because things will be left out or glanced over. However, this is not to say a good video game movie is impossible. What needs to happen is a video game movie that makes absolutely no attempt to condense the plot of its source material into that three-act format, because that's where the problems start. Instead, a good video game movie should be built from the ground up. To be blunt, disregard the plot of the original game in favor of making your own plot that stays true to the spirit of the original. You'll have more freedom to include or leave out characters and plot points, and can form a more cohesive story with good flow.
EDIT - How I'd do a FF7 movie, have Cloud still in AVALANCHE but Sephiroth in Shinra and Aerith being held in captivity as a test subject. First film would cover AVALANCHE fighting Shinra and rescuing Aerith from them, as well as Sephiroth's turn to madness leaving up to the Nibelheim incident and the battle in the reactor as the climax. Leave Sephy's return, the Black and White Materia and Aerith's death for a potential sequel, then just remake ACC better for a triology.