I like it!
The minimalist art was really polished and well done. In fact, the whole look and experience was refreshingly clean. However, the controls and game mechanics weren't very intuitive. When introducing new mechanics, it would have been extremely helpful to have a text description of how to interact with them, like an in-game tutorial.
Also, I noticed that when using a laptop's mousepad one needed to double-tap even if the hardware settings are set to single-tap. This turned the "x2" box into a quadruple-click, which could get tiring. This was consistent on multiple machines.