Very simple, but has it all!
For such a simple game, this sure is addicting and fun to play!
Though the story isn't even told, there actually is one, and quite a pretty one too. I got to the 'double hot' ending, but I'll definitely try to go all the way to unlock all the medals.
The thing that is good with gameplay is that you're going down instead of up - I don't know about how community looks at that, but personally, I think it is much more relaxing. Matched with that wonderful tune (by the way, did I hear it already somewhere?), it is a challenging relaxation that can attract people of any ages.
It is actually quite easy when you first look at it, but then you realize you have to be careful about spending your energy falling around, and that strategic note of the game is something I like a lot. You don't just go running around, and hurrying before the screen edges crush you - you are trying to make a safe descend and reduce the Fall Damage. (see what I did there? ;P)
All in all, quite a game, on first sight maybe even too simple, but brings a lot of fun, has a nice ambient, and is addicting - a fine example of 'less is more'. :)