Your sample it's cool but it seems to accelerate during jumping...
That's due to the bullet behavior plus scroll-to behavior. Infact if you jump when the layout is not scrolling it does not accelerate.
I set also position of background during jumping and falling( TiledBackground set position (TiledBackground.X+4, TiledBackground.Y) and it solves the acceleration sensation.
The problem is that when your reach the end point of layout (and your player is facing to the wall), during jumping tbe layout can still traslate outside window xD.
I'll try to find a solution! <img src="smileys/smiley36.gif" border="0" align="middle" />