For the last week and a half, we have been following the first section with Titus. He loves listening and now recognizes Joseph Hyden's surpise symphony. I am also getting better at playing it on gentle piano for him. He likes dancing to it.
The best part is that when we go to play the guess key game, he actually tries, he looks for the note (given his attention span at this point for this is about a minute).
Also, with gentle piano, he can play the first few notes of hot cross buns. I do have to remind him of the note by singing and sometimes pointing, but he makes an effort to actually look for it. I have tried video taping him in this process, so far to no avail. As soon as I get out the camera, he loses interest or tries to go off to play.
See results for some games below: