@RDisher and sharethepain: you have to take the second door, and go near the trap on the floor. Try to walk on it, you get killed. Take the second door again, go near the trap, and wait for the flying thing/shopkeeper to be close to you. Then, walk on the trap, and HOLD the down key. The shopkeeper get killed, and after 5 sec., the floor goes up. Then go back and take the third door.
Just for your information, there IS a reset button. The game autosave each time you go in a new room, click Menu, click Play, then Continue, and the room will be just like when you went in first. Please + so that people stop complaining about no reset.
@NinjaMafia: it's because of the "???" blocks, who give +10 in a random stat. That's why the number of points are not the same. You just got lucky with dexterity, that's all.