As mentioned on somebody's awesome redo of the Palace Of The Silver Princess maps, the old-school D&D style lacks door-opening-direction info. Amend it!

Another thing that bothers the holy-be outta me is the 10' grid. Now, there's nothing wrong with a scale system per se, but it seems to me that the 10' grid encourages dungeon designers to make 10' wide hallways, or even 30' wide hallways ... and we get these humongous 330'x590' rooms that are just absurd. Come on! You guys ever visit any medieval buildings? We got Brits in this forum come on, speak up: the doors are like 2' wide, the halls 3' wide. The hallway in my modern (i.e., not medieval) house is not 10' wide. My bedrooms are somewhere around 120'sq, which would be a little over one square on the grid. OK, I live in a small house, but I hope you get my point. Let's see some hallways that take HALF a square on that classic TSR 10' grid! Let's really think about scale, please! Don't let that darn default cyan grid overpower your common sense.