there are already other sites with all those , but 3dshooterlegends is the best ( for me as it has those yahoo and come2store instead of rapid/mega links ) .. why not all genres!
Simply because it's way too much work for the team to do. Even a few persons are doing hard on just one genre. Now that there's Adventure Legends, there's even more to do.
It was planned to have more genres of course.. but as this isn't just a site with uploads but also information, it's getting more and more to do with every game entry.