I like the content, music, and overall vision for your cock hero
for the beatbar all id say is maybe make it less intrusive if its not hard to adjust in your finished rounds, like just sliding it down slightly on screen so less of it is showing I think would be better if your focus is on simple endurance style beats, that way your eyes won't be as drawn to it, but its not a big problem for me either way
As for the last round (assuming g you mean this as separate from the reward round) ill toss out some ideas to see if anything inspires you
- Endurance round where 100% there in some kind of pov handjob or other thing on screen completly beatsynced (maybe with a completly constant beat) could be a cool effect switching between scenes but always having the synced handjob/blowjob/pov fucking from each, could even switch between 3D and real (im a little biased

) If you havent already put this concept in I think this with a little teasing text during or before, maybe warning you about the non stop aspect, would go a long way
- Heres another idea I've just thought of and might want to put into one of my cock heros but having some cum shot scenes partway through the round, but then in sync with some music/ beats, reversing the video so the cum visually get sucked back in, again could be accompanied with teasing text saying not yet or some variation of that, just building anticipation for the reward round. If you get the right music for it this could be good, even just having a bunch of cum shots, then having a rewinding tape sound and you reverse the shots, maybe with a vcr filter, then keep going with more endurance stuff
Hopefully that helps give you some inspiration even if you don't use the ideas at all