Blast from the past. I havent heard or seen that for 15 years. It felt so cutting edge and cool at the time.
Parasite Eve. I know there was a movie out already based on the book, but I'd like a film based on the game that takes place in snowy New York City. I still play that game to this day because I love the atmosphere of it so much.
Other. The Gabriel Knights games have better stories than most horror movies. Especially the first one, Sins of the Fathers, which is the best voodoo-related story I've ever come across.
I remember Night Trap! So controversial until you actually played it. I'm gonna go with the crowd and say Castlevania, because it has so much atmosphere and potential. The soundtrack would kick ass. An awesome Castlevania film will never be made, however, and if whatever rumored project does see the light, we all know it will be filled with tried one-liners and a soundtrack featuring "Let the bodies hit the floor! Let the bodies hit the floor!"