I agree. The controls are annoying. Mouse controls that let you fill in an entire row would be far better. However, good concept, and I'm pleased to see nonograms because I love them.
The only reason the first Music Catch isn't the best game ever is because this game came out. It's beautiful, calming, well-designed - this is my standard for a five star game.
I gave it 3/5 because you could do something with the concept. If this was a test to see if everything worked before you made a game of it, then kudos. If this was the game, maybe not so much.