Great puzzler! The music really puts you in the mood too.
I got stuck on level 1 due to the lower half of the screen not responding, but refreshing the page solved that. Some fullscreen thing probably. After that I got through all of it!
I would love to see how it'd play out if you had to choose to split blocks either horizontally or vertically. That way you'd have a lot more decisions to make with limited hammers.