These anime are set in or feature video games. The cast may be trapped in a video game, or are playing it for leisure or fame. The majority of the story is set with the cast playing video games and interacting with the world...
Anime series, OVA's and movies I've seen that I felt were a huge disappointment, or just plain dumb. Stay away. Not necessarily the worst out there, but bad enough. Note, these are only the ones I've managed to finish...