Interesting, but it shows the first note, and after you play it, it shows the next note, so I have to not to look at the notes when trying to guess them.
Also, too complicated for a beginner, I would start with things like "guess which note is higher" or "how many notes are played simultaneously".
As a beginner I can say that I cannot hear notes and intervals, but I can hear if they go up or down, and I usually pick the notes by playing different notes and comparing them. But your app makes me start from the beginning for every mistake, so it becomes a little difficult.
Also, too complicated for a beginner, I would start with things like "guess which note is higher" or "how many notes are played simultaneously".