I almost like all video games genres and its themes (future, modern, anime, dark, sad, etc.), but I divide into 2 categories of video game classification:
1. General or mainstream, such as FPS/Action (main genre) , Action-Adventure, Platformer, Simulation, Strategy and Horror)
2. Niche, usually pure adventure games, puzzle games and visual novels (secondary genre)

Friends accepted by case-by-case manual flitering.