By the size of this thread, I figured "Doors" must be a pretty good little game, so I decided to give it a shot.
I've been able to access two rooms and have picked up cube pieces, letter pieces, a picture and a card. Unfortunately, I can't do anything with any of those items. I assume the picture contains the code for opening the safe, but when I press the corresponding numbers on a telephone dial, nothing happens. I also assume that I'm supposed to put the cube together, but I can't figure out how to do that. Ditto for the letter pieces.
Any hints to get me started?