I just tried this yesterday and it's very great and exciting. I'd like to suggest an audio visualizer per each player so we would be able to distinguish the instrument the user is playing and know who's playing or not/ or spamming. It's sometimes a hassle when you are in a middle of a song then somebody interrupts your jamming. You have to take time muting each player just to find out.
btw, thnks for developing this program! I like it a lot and told my friends about it.