Yeah I figured as much. I came back and defeated him now and it was fine.Argueably, the purple guy is better left later in the game. I don't think you're suposed to defeat it so early.
I think I'm coming around a bit on the gameplay now that I realized you're supposed to just go ham with attacking constantly while throwing in parries and dodges without ceasing your attacks. Playing defensively sucks shit in this game and perhaps trying to do that was my main problem with the gameplay.