Even though the movies deviated from the original concept of the first couple video games, the Resident Evil
movie series is pretty good. It definitely encapsulates the cliche zombie plague genre well, while having it's own unique plotline. Even if that plotline includes having super powers by the fifth movie....
Some less-than-remarkable movie adaptations of video games: Super Mario Bros.
, Final Fantasy: the Spirit Within
, and Doom
If I were to wish for a game franchise to be adapted into a movie, I would pick either Sins of a Solar Empire
PC game, or the tabletop/PC game Warhammer 40K: Dawn of War
For the former, I would imagine the plot is open-ended enough to justify a nice epic 3-way space battle with massive titan warhships having a slug fest. Kind of like that one big EVE Online battle.
For those who have never played Sins of a Solar Empire
For the latter, there is practically an unlimited supply of lore that can be drawn from the Warhammer 40K universe to make an incredible movie. It would need some seriously badass voice actors (as all Space Marines sound like Bill Pullman giving his Independence Day rally speech), nice CGI to do the demonic warp spawns, and a lot of close ups showing Orks getting their faces shot off, xenos getting power-punched in the face, and Chaos Lords taking a chain sword to the abdomen.
Basically the movie shouldn't go more than five seconds without seeing blood, gore, and hacked limbs flying through the air.