You know how in Bloodborne you have all of that combat depth through the use of items, exploiting weaknesses down to damage type (like serrated or thrust), and also things like transformation attacks, rolling attacks, running attacks, charged attacks, backstep attacks and the list goes on?
Well, if someone said that Bloodborne's combat is just hitting R1 to attack and O to dodge, they wouldn't actually be wrong, as it is completely possible to go through the game with just that, but it's an oversimplification that sells the game short compared to what it offers.
Since you played the Platinum Demo, check this out:
https://www.youtube.com/watch?v=bV-ANQvMkXg
If you want to put in the work, there's a lot more to it than just holding O.
And it's not just for flash either, most of the moves he's using in the video have a large amount of iframes, making them excellent ways of avoiding damage, especially since there are some attacks that can't be dodged by holding square. He's also great at managing his MP, which is fundamental in this game.