Btw, I've been playing around with your capx recently and tried to add 3 more floormarkers.. Got a noticable FPS dropdown : way too many individual sprites.
Using TileMaps is waaay more efficient FPS/CPU-wise.
Take a look at this example!
Actually, it's first time I've tried tilemaps, and I see a HUGE perfomance boost:P
Yet another little "magic trick", thought it might be helpful;)
(P.S. Omg, THIS is hot :D)