Got in a few hours with Bloodborne yesterday. I'm not very far in, obviously, but so far it's exactly what I expected. It's clearly a Souls game -- the engine, art direction, inscrutability, difficulty, UI look, etc. all look like they could have been Dark Souls DLC. That said, the combat really does play pretty differently. There's no magic to speak of, so you can't fall back on Firestorm or Homing Crystal Soul Mass to cheese enemies. There are also no shields, so you can't just stand there and tank enemies either. My guess is that those two changes eliminate the play style of 95% of the people who played previous titles, me included. Instead, you have to fight aggressively and with a sense of urgency. You're going to take damage on a fairly regular basis, but you can recover some or all of the damage you just took by retaliating quickly. Whereas in Souls games, you instinctively back off to recover if you get hit, in Bloodborne its often better to double-down by hitting back first. There's also a big emphasis on the parry-and-riposte mechanic, which in this game relies on using firearms to stun enemies. The melee combat is different, but still fantastic and addictive.
If you've played Demons or Dark Souls, you'll recognize a lot of the same basics and adjust pretty quickly. I only died a couple of times before reaching the first boss, and that was due mostly to not having the controls mapped out in my mind quite right. For some reason there was no fog gate warning me that I was entering the first boss area -- I wasn't prepared and died to him on my first attempt, but beat him with no serious problem on my second attempt. But I beat Demon's Souls 6-7 times and Dark Souls 3 times; this first area feels like a tutorial. People who are new to these games are going to find this very challenging. Bloodborne throws some fairly large mobs and ambushes at you right off the bat, presumably to teach new players the importance of moving slowly and cautiously and drawing stragglers away from the main group.
My early impression is that character builds are going to be a little dumbed-down. There are far fewer weapons, and I believe there's only one possible upgrade path for each. I also don't think you can upgrade armor. One cool aspect is that most weapons can be switched back and forth into two variants. For example, I'm currently rolling with a longsword that you can plug into a big giant metal block to convert into a two-handed hammer. Each weapon has more versatility than a standard Souls weapon would, but I haven't decided yet whether that makes up for the smaller number of weapons and lower amount of customization overall.
It wouldn't be a Souls game if it didn't have some performance issues. Apparently this game doesn't even lock in at 30 fps most of the time, which is hard to believe because it's not exactly a graphical powerhouse or anything. If you decide to roll through a big group of barrels, expect a slideshow. Loading times when you warp between areas are just long enough to be slightly annoying. These are minor issues though -- certainly nothing game-breaking.
So far, so good.