Intervals: Name the other note. Press the button to switch between Harmonic/Melodic. Enter answers in the form of letter name then accidental, don't use double sharps and double flats. (e.g. C#, Db, all enharmonics are accepted except ones with double sharps/flats) If you get it right, a new question will appear, if not, the same one will appear. To replay, enter "again" (or you can just press enter)
For my other ear-training project see https://scratch.mit.edu/projects/377858384/