I'll comment based on the criterias along with the score I gave out of 5.
Game Design: 4
I've noticed that you can occasionally hit people that are behind you. So if you just stand still while spamming attack, you can survive for quite some time, since you heal for every kill.
I like that out of the 3 possible people, 1 of them is passive, making them viable if you are low on health.
I see there is a lower and an elevated area, but I didn't notice them until I got near them.
The difficulty increase is not noticeable, if there is any.
Fun: 3
As mentioned above, since the difficulty doesn't increase, if you played the game for long enough, you will be so skilled that it's nigh impossible to die. As such, you get bored easily if you played for a long time, though not if you just played for a short time.
Innovation: 5
The idea of bystanders being aggressive towards you when you assault someone is quite uncommon- the other one I could think of is when you hit a zombified piglin in Minecraft.
Theme: 4
"KOs"... what a (pun)ch! Anyway, since people are hostile towards you as soon as you hit someone, the scene indeed gets chaotic quickly. A (fist)astic interpretation!
Graphics: 4
I feel like it's a hybrid of arcade and that block game. Looks good.
Audio: 5
I see some people commented about that punching sound, and I can say the same about it. Everything else works fine as well.
Conclusion
The main issue I had with the game is the lack of difficulty increase. Other than that, the game is pretty decent. Keep up!