Level 17 is so far my hardest level (I'm stuck there as I'm typing this.) The top moving platform is so hard to time with the small one under it and the jumping and fluid movements. Along with the platform you have to go up to get to said small moving platform, it's curved just right that you get stuck and the timing gets even more off. Some of the other levels were easy to beat and others worse, but so far, from my experience, Level 17 is the most infuriating one I've died on, and am still dying on it.
But other than what I've said above, this is a really amazing game! I love it and the ice cube itself. The face on it makes me kinda sad about having to forcefully kill it when I screw something up.