I’m French but try to put this in English, so please forgive the mistakes. This is just the best I’ve ever seen concerning sight reading. The locking system progress, the progressive difficulty, the size of each lesson that you can practice at your own rhythm, everything is made to improve your sight reading. If the app was complete, the fifth star would have been there, of course. But it seems to be a work in progress, so let s hope new updates will come soon. A huge bravo for your great work, guys.