I gotta say. Props to you for this idea. You made use of the limitation, the concept is pretty interesting, the gameplay is really challenging as well. The art is not so bad either, but that's not really the point as much. I feel level 2, 3 and 5 were the hardest and took quite a bit of thinking for me. Fantastic job on this game!
I do have to probably note, you stated all levels were possible, but for level 7, I inputted a whole bunch of commands but its like my angels weren't even moving at all for some reason and they were stuck and I couldn't create a sequence for them.
Also, I feel it would of been nice to add a speed up as well with what someone stated in the comments. I wanted the process to move faster as I was figuring out the right sequences.
Also, this is off topic, but your sliding background was revealing a little bit when you look in the menu for quite a bit.