Guys this is still a lot of choices. You need to put yourself in the head of the casual RG user that just knows a bit about games; he's not gonna fill 25 categories about things that he barely knows! Not everyone knows game publishers and engines, nor the software house which produced their favorite game. Here's what I'd keep:
Best Original Soundtrack
Best Game Design
Best Narrative/Writing
Best Innovation
Best Male Character
Best Female Character
Best Cast Ensemble
Best Game Engine
Best Casual Game
Best Horror Game
Best Racing Game
Best Strategy
Best Fighter
Best Sports Game
Best Multiplayer Game
Best MMO
Best RPG
Best Third-Person Shooter
Best First-Person Shooter
Best Action-Adventure
Best Handheld Game
Best Nintendo Wii Exclusive
Best Playstation 3 Exclusive
Best Xbox 360 Exclusive
Best Game Franchise
Video Game of a Generation
Casual games will incorporate puzzles, music and party. Also, I'd make the 'Best categories' votes optional. Not everyone plays a game of each genre and might not have a preference!