Currently when you fail or miss in a song and you want to re-watch what happened the replay system does a poor job of showing your mistakes. Not only can you not even watch the replay more than once unless you record it with an external program but you can't even efficiently view your mistakes( some songs can be lengthy and often times you can't even fast forward). One of my suggestions to improve the users experience and add overall better functionality to the replay system is to represent the misses and song failure on the Progress Bar directly.
Here is a rough image showing my request.
Red = Fail
Orange = Miss
Here is a rough image showing my request.
Red = Fail
Orange = Miss