The best game made into a movie

[Majin-Tenshinhan]

The OP is really weirdly worded. If you mean the best video game-based movie then it's definitely the first Mortal Kombat, because it captures the spirit of the game well and is actually pretty good (please note: FIRST MOVIE ONLY).

If you mean the best game series that has gotten a movie (which the thread title actually sounds like), then I'd say Mario Bros. followed by Resident Evil.