I like it.
I don't think I understand clue 3 though.
"3.You could pass this door twice as often as others."
I work it out that with all the clues I am left with:
6, 12, 18, 24
6 (1x6, 6x1, 2x3, 3x2) total 4 ways
12 (1x12, 12x1, 2x6, 6x2, 3x4, 4x3) total 6 ways
18 (1x18, 18x1, 2x9, 9x2...