I spent points on the unlock for it, where are you meant to find the Piano room in this game?
The piano room is a game room. It won’t show up in every level as the game rooms don’t appear too often. Most of the time, these rooms will be locked by a fruit machine where you have to pay coins to match three items. When you get it, the block will vanish.
To find game rooms in general, look out for the neon sign that has a classic game controller on it. The square base with a stick on it. Head inside and you will be able to spend more coins to play the piano game.