I wouldn't rate it as bad as many people below me did, but there are a few things lacking.
Okay, my first major complain, the filesize, for those graphics it shouldn't take up 11mb. Normally i would say its the fault of the music, but as i didn't hear any music, probably due to a bug, i can't say anything for certain.
The graphics need a lot of work, take the menu as an example, it looks like graphics you found out of google. You really should draw them on your own so that they will match each other. Find some tutorial on how to do them in a free art program or in flash.
And since i'm at it, i wouldn't do the game-graphics in flash, it would look better if you created pixel(as in drawn by a program like Gimp or Photoshop) art and not vector for it, since they are static graphics to begin with.
The programming seems to be okay, aside for the music bug. But, even though the falling speed seems to be realistic, it made playing it quite difficult, as you may take too long to fall...too be honest, i wouldn't know how to fix this haha.
As for gameplay, it's a nice idea, but not very exciting. When i saw the preview image and saw "space fall unlimited" i expected actual falling throughout the entire game, not just from platform to platform, staying in the same square the entire game.
Also some kind of score might be nice, so that the player gets the feel of having to surpass his previous score thus giving it a replay factor.
To sum up:
Add a score, make graphics that look good with each other, preferely not-vector graphics, and you should have a solid 4 star. (and of course fix the music bug) It doesn't take more from there to make it a 5 star game in my opinion.