Yeah, that centaur fight, you're basically guaranteed to lose if you don't hit them EVERY single time, and not only that, you might not be damaging them enough to make up for the difference in the health that you lose to them. And even then, the barrage move they do is one, super accurate, two, absolutely op, even if you prioritize vitality (That's also pretty bad because in this game, Higher DPS means a lot more than survivability nine times out of ten), and three, is seemingly random. There's no line that says that they are specifically preparing the attack before they unleash it in a previous round, it's just random. Unless I'm mistaken, and I'm just not remembering it right.
AND ON TOP OF THAT, they also have really high evasion, so if you don't focus on leveling up speed, you are just not going to hit them, nor are you going to dodge their attacks. AND ALSO ON TOP OF THAT, trying to escape them is nigh on impossible, or at the very least, highly unlikely. It seriously reminds me of how necessary it was to have AGL in Dark Souls 2 if you wanted to dodge something properly. If the dev is not currently looking into how to properly balance a game like this, I'd highly, HIGHLY recommend they do so. If you want the game to be fair, but challenging, that'd be fine, but I don't know how well that kind of thing translates to what is essentially a text adventure game.
Also, last thing, but why do enemies give diminishing returns of EXP when you level up? EXP is literally also used for buying things in the game, and yet if you want to routinely use those items in combat, you'll be grinding for what feels like hours, which is incredibly monotonous. In a game like this, which is already bordering on repetitive, that's clearly not a good thing.