Feedback on my piano collaborative jamming over backing tracks website

Hi there,

Just thought I'd upload this here to see if I could get any feedback on my piano collaborative jamming website.

At the moment I think the blocks you play might need to change size ie. there all 8 bars long and maybe get rid of the inactive 4 bar gaps. Was wondering if there was anything I could add that would make it more gamification if it really needed it, also later on may add the feature of customising your own synth sound, maybe include sampler to sample real instruments if possible,

Thank you for any feedback,