I personally didn't notices the changes for stats when killing enemies. Maybe I'm not in the right spot? If that's the case, then there should be a lot more clarity on where you actually are in the world. Something as simple as a label above or below the score displaying the name of the section you're currently in. The enemies also only deal damage on touching you. So, if you parry, they'll become a human shield.
That being said, I think the idea is pretty cool. A vampire survivors where it's not about exp, but where you kill the enemy? Great idea, I hope to see an update for this sometime!