I was pretty surprised at how much I enjoyed this. I think its biggest strength is probably how it's so simple. It's truly interesting to see how far you can go with something. There are always new obstacles to overcome. I thought it was a level game at first and you were supposed to go through the vortex.
I now realize that killed me. Funny, there weren't any in the long game I played afterwards. There should be more games like this. It's actually quite challenging. Could use a bit more details, though.