Do you have a gentle hint for 'Around a Corner'? The two loose blocks have caused me to wonder if I've missed a mechanic!
edit: a-ha! Sometimes asking a question leads you towards an answer :-)
The puzzles so far have been great, though I do wonder whether it might be worth allowing progression to the next floor after beating a 7-8 of the current floor's levels, so that progress can continue even when you run into a stubborn level? Perhaps you could gate the final set of levels around 100% completion?