When I first started playing, I was afraid that this game was going to be really bland. I was expecting the entire game to be nothing more than weaving your way through ledges in order to land on a ground so that I could reach the exit, and that was that. Up until the spikes, the game was exactly that for me. The only reason I kept going was for the sake of giving this game a fair chance; it didn't look like it was going to be long, and I had nothing better to do, so why not?
I'm glad I kept playing. When I reached the first level with spikes, I realized that there would be far more to the level than just weaving through ledges. The spikes added a brand new layer of challenge to the previously-easy task of falling to your death. As more and more mechanics were introduced, I started enjoying the game more and more; by the 3rd-to-last level or so, I was thoroughly enjoying this game.
With that said, Rock Bottom is a quick, enjoyable game; unfortunately, by the time all of the game's obstacles and mechanics have been introduced, it took only a couple more levels to beat the game. Because of this, it feels as if the entire game is shorter than it should be. Don't get me wrong, the levels used to introduce the spikes and sand were pulled off wonderfully. I just think that it took too long for the spikes to be introduced after the falling mechanics have been fully established, leaving me with the impression that this would be a bland, boring game. Once I got to level 13, though, I started to love the mechanics and the challenging levels. Heck, I was impressed at how much of a puzzle level 14 was, since I was trying to find out how I was supposed to build up my jump meter.
Overall, I think this game earns 4 stars. I'd like to rate it 4.5, but I feel that first impressions are so important to making sure that a person keeps playing your game. A poor first impression can easily drive a player away from even a fantastic game, which is what almost happened to be with this one. The blowing wind also bugged me a little, since it sounds too much like a person inhaling. Despite the flaws, you did a great job on the gameplay itself, and I had a blast playing through the last two levels.