Hmm, a little bit mixed on this one!
On the positive side, the rhythm game mechanics seem pretty solid. The note charts felt well-timed and to the beat, the notes were properly color-coded to show their type of beats, I liked that you showed that note charts can also have interesting tricks like delayed notes, and so on. The game also just felt polished in terms of presentation, menus, UI, and all that. Certainly feels like you've got a good base to work from for future development!
On the negative side, I don't feel like the connection between boxing and rhythm was made. It felt like I was just playing DDR, but you replace the typical music video with a video of two dudes boxing. Ideally, when I'm hitting the notes correctly, I should feel like I'm having an effect in the fight, like my punches are happening to the beat, but it didn't have any sort of feedback at all and felt like two separate things were happening. As a minimum, I would create better sound effects for hitting notes, with variations for whether you are attacking/defending and how well you did: perfects should be giving me loud cracks, greats/goods should only be giving me jabby puffs, and so on. The way the fight is presented and animated could probably be done better as well: dunno why it has to be so zoomed-out as it further adds to the sense of disconnection, like are we playing as the fighter or the coach here?
If anything, I would actually prefer if the combat was less reciting a note-chart perfectly and more like Punch-Out or other rhythm games like Necrodancer/BPM where you are free-form deciding when to attack and when to dodge based on the opponents movements, all to the beat of a song for extra damage. But I understand that's asking for a totally different game, I suppose.