I suppose you mean a category for Brains and Physics. Puzzle and Skill are basically the same thing, and besides, we have a large amount anyways to fit all of our games. I don't think we need to add any categories for a while...
Armor Games isn't responsible for making all the flash games on the site. If you'd like to see more games on the site, then you should either make them on your own, or ask a developer from another site to create it then submit it to Armor Games.
Puzzle and Skill games are Brain and Physics games. If you look through them, then you'll find that they are. Also, about the difficulty part. That's depends on the person, I find many of the Puzzle and Skill games to be rather easy, but I see comments on them about the game being difficult. It's a matter of the person's perspective on the game. But I will tell you, there are difficult ones out there if you look through the pages. Some do take a few hours to actually complete while others only take about ten-twenty minutes. But again, that's from my perspective on the games. Yours may differ from mine.
I think that the categories that AG has now are sufficient. It puts the proper games in the proper category and it's correct. However, there isn't an all category on this site unless you change the name in the address bar. But on AG3 there is an all category, if you were wondering about that as well.
