Really? I skipped the rules as well and understood the mechanics after about 10 seconds of playing.
It could be the browser that I'm running it in. I couldn't figure out how to move the selected box. I tried clicking and dragging, etc.
I implemented swiping, and the mouse cursor should be able to do that as well. The arrow keys are the intended mechanism for how to move the selected box. I'll see about adding an overlay to the first level that explains it more intuitively
I know that I should have read through the instructions, but I'm sure there are a lot of people like me who just want to jump in and play.