The DLC level for Bloodborne is considerably easier to access than the DLC of the first Dark Souls. You only have to beat a mid-game boss, and the items that you need to access the DLC are literally just handed to you next time you visit the Hunter's Dream. Unfortunately, if you don't read the pop-up text that tells you where to go to access the DLC level, then you might be in trouble, as there's no other indication in the game of where to go. Not eve in the item description of the trinket that grants access. In typical FROMSoft fashion, accessing the DLC is fairly obscure and un-intuitive. In fact, it's even more obscure than Dark Souls because it isn't something that the player is likely to accidentally stumble upon. It requires players to do something that they might actively avoid attempting to do because it's something that probably got them killed in the base game. Granted, there is one other situation in the base game in which you are teleported to an optional location by this same method, so it's not entirely unprecedented, but it still feels contrived. Look FROMSoft, if you have to explicitly tell the player where to go in a text prompt, rather than allowing the player to infer it based on textual or environmental clues, that's probably a sign that you made it too esoteric...
The DLC doesn't require players to jump through as many hoops as Artorias of the Abyss required,
but the actual entry-point into the DLC is even more obscure and counter-intuitive.
Once you're in the DLC's "Hunter's Nightmare" area, you'll be provided with a seemingly much more technical challenge than Dark Souls' Artorias of the Abyss DLC. While Artorias DLC threw a lot of magic-casting enemies at me that required me to cheese my way through the levels by using ranged weapons or mob-baiting tactics to cut down enemies one-by-one while staying out of range of the casters, Bloodborne's The Old Hunters DLC instead pits me in more one-on-one battles with fellow hunters that require more careful technique in order to vanquish. In fact, these encounters kind of subvert one of the common criticisms of the Souls games, which is that enemies are too easy to bait, and fighting one-on-one trivializes most fights. The mob monsters in the Hunter's Nightmare actually back away from you as if they're scared, and the other hunter enemies will actually kill those monsters for you, setting the stage for these one-on-one fights. I hope you've been practicing parrying, visceral attacks, and dashing towards enemies in the base game, because this DLC will test those skills. They aren't as obscenely difficult as the NPC hunters that you can find in the chapel of the Unseen Village or in the courtyard on the side of the Grand Cathedral (opposite the path to the Forbidden Woods), but they can easily destroy you if you overreach or get arrogant.
Or at least, most of the hunters aren't that difficult. There are a few notable hunters that posed quite a challenge. One pair of hostile church agents caused me quite a bit of trouble with the camera and target lock, since one was a ranged spell-caster, and the other was an in-your-face swordsman. These issues were exacerbated by the presence of environmental decorations that kept getting between my character and the camera, and thus blocking my view of the action. It always annoys me when game designers put challenges in the game that the mechanics are ill-equipped to deal with. It's something that Bloodborne and the Souls games rarely fell victim to (other than the occasional tight-roping and platforming), so it's really noticeable when it does happen.
This wheelchair enemy would sometimes wind up on the moving stairs and turn invisible.
There was also a recurring glitch in which a particular wheelchair enemy would sometimes fall onto a set of rotating stairs and would then become invisible. I'd be walking around, then suddenly BOOM! I'm blasted with gatling gun fire literally from nowhere! This resulted in two cheap deaths for me before I realized what was going on and remembered where it was.
Through the nightmares of hunters past
Another way that "The Old Hunters" is reminiscent of "Artorias of the Abyss" is that this DLC fills a similar role of further expanding upon backstory that is hinted at by the base game. Wheres Artorias literally took the player back in time to witness the legend of Artorias first-hand, "The Old Hunters" sends the player into a nightmarish limbo version of Yharnam populated by hunters and church members of ages past. The world is twisted and convoluted by the imperfect memory of the characters that inhabit it, and the result is another confusing trek through the maze of a barely-recognizable Yharnam.
The Hunter's Nightmare is a twisted and threatening re-interpretation of the familiar Yharnam.
But this time, the maze feels more organic. The opening level of Yharnam in Bloodborne really felt as though the developers wanted the player to at least have an idea of where to go, but just failed miserably at communicating any sense of direction to the player. For example, an NPC in original Yharnam told you to go "south", but there's no compass or signpost indicating which direction "south" is. In this nightmare Yharnam, I feel like direction is deliberately left ambiguous. The world itself feels like a surreal mystery that the player is supposed to unravel, and the first part of that mystery is answering the questions "Where am I?" and "What the heck is this place?" And the fact that Bloodborne already requires the player to go through portals and trek through nightmares makes the transition to the DLC area feel much less jarring and out-of-place than the journey to Oolacile felt, even though (as stated early) the entry-point is more esoteric than ever.
The DLC doesn't remain this abstract forever though. After defeating the DLC's first boss, you progress into a giant research lab with a rotating staircase similar to the Duke's Archives of Dark Souls. But in typical Bloodborne fashion, the similarity is actually closer to Demon's Souls. It's a long, grueling, vertical maze that evokes the Tower of Latria far more than the Duke's Archives. It's morbid and full of mangled botched blood experiments conducted by the church. Perhaps Latria desensitized me, and so this laboratory never got quite as chilling as Latria. The research lab's handful of NPCs offer ambiguously intriguing quests and red herrings. I fought with the desire to try to help them, or just put them out of their misery.
Your new weapons can be a godsend against the tough enemies of the fishing hamlet.
Leaving this research hall is where the DLC gets really intense! The creepy, deserted fishing hamlet is a hive of tough monsters and magic casters that can kill you before you can blink. The large fish creatures are harder-hitting and more resilient than some bosses, and I was dumbfounded that they were standard, respawning enemies, as opposed to mid-level mini-bosses that could be permanently killed. But just like the giant warthog monsters in Forbidden Woods, the fishy behemoths will still be there waiting to pummel you with a ship's anchor whenever you respawn.
Old Hunters League feels like a dead end
And when you leave the Hunter's Nightmare, the new content isn't over. You can now use the new "Old Hunter's Bell" to summon NPC Old Hunters for some of the game's key bosses. A new covenant was also added (via fee patch around the same time as the DLC) called "The League". It provides some small rewards for cooperative play. League Master Valtr can be met in the Forbidden Woods, and joining the leage allows you to summon Valtr in a couple areas of the DLC and base game.
The League doesn't really do much though. Leveling in the League provides a gesture, an ugly piece of armor, and a modest rune. As far as I've found, there isn't a competing faction for The League, so it kind of feels like a dead end gimmick. It provides a little bit of lore that actually reinforces some of the other elements of the Hunter's Nightmare. There is also a hunter character that shows up after you resolve the League quest. I'm not sure if he's intended to be in some kind of opposition to the League, but he does drop a powerful new tool when defeated.
Various new summonable NPCs are in the game, including new covenant characters.
I feel like this League quest dead-ends rather suddenly and abruptly. I've read that Bloodborne was originally scoped to have two DLCs, but that they were combined into one for whatever reason. I get the feeling that the League was probably originally intended to be its own standalone DLC, but that it was merged into The Old Hunters updates. After Valtr disappears from the Forbidden Woods, I get the feeling that there was supposed to be some longer questline in which he appears at other locations on the map, providing more backstory, and that there was probably supposed to be some kind of counter-League faction that was pursuing him. As in traditional FROMSoft fashion, the League's mission would probably have been revealed to be less benevolent than it seems, and the player would probably have to chose between the two factions (just like you chose between the Executioners and the Vilebloods). For whatever reason though, this seems to have been scrapped, and all the League does is provide a very short, dead end side quest with modest rewards and a leaderboard that will be instantly full of people who took advantage of some in-game exploit to max out their scores.
UPDATE: APRIL 4, 2016:
After thinking about it some more, I don't think that the League was supposed to be its own DLC. Instead, I think that the opening part of The Old Hunters (the "Hunter's Nightmare" ) was probably supposed to be expanded into a larger set of levels and its own DLC. The remainder of The Old Hunters (the lab and fishing hamlet) would then have been their own DLC. The League might have been part of either of those two packs (probably whichever one the Hunter's Nightmare ended up in).
The reason for this is that the Hunter's Nightmare feels very disjoint from the rest of the DLC. It's an explicitly surreal, nightmarish location with warped geometry, but the lab and fishing hamlet look more like real places that probably exist within the game's universe. In addition, the hunter enemies of the Hunter's Nightmare do not persist through the rest of the DLC. From a lore standpoint, the DLC drops the pretense of being in the collective nightmare of hunters, and instead shows you real places that gradually challenge everything that you thought you knew about the Blood Church and the Old Ones. So in the end, it feels like this idea of Hunters coming to the nightmare in search of "forbidden knowledge" was just used as a framing device in order to stick the Hunter's Dream onto the rest of the DLC.
But the new weapons are worth it!
Where The Old Hunters makes up for the lackluster League is in its new weapons and equipment. There's some really nice new weapons in this DLC. I'm particularly fond of the Whirligig Saw, which is basically Bloodborne's equivalent of a chainsaw. And that fondness was before I discovered its L2 transform attack! It has charge attacks that can deal continuous damage to opponents as long as you have the stamina to hold the weapon, and the multi-hit characteristics of such attacks makes it an ideal weapon for your poison blood gems, and a dangerous PvP weapon. There's new weapons for virtually any character build that you might have imagined. Even Arcane-based characters have the awesome new Moonlight Sword to pair with their Ludwig's Holy Blade. And if you're a little pyro-maniac, then the Boom Hammer is right up your ally.
The Whirligig Saw is a fun new weapon that opens up some new methods of attacking.
There's also some new heavy guns, including a rifle, gatling gun, and another cannon weapon. The Church Cannon isn't as strong as the regular cannon, but it has lower bullet cost and can be used for different purposes. The cannon ball arcs downward, so you can manually aim the cannon upwards to use it as a makeshift mortar. And of course, gatling gun's are always fun. There's a slight wind-up delay, and it'll understandably chew through your bullets pretty quickly, but it is oh so satisfying! Heck there's even a new shield and a melee left-handed weapon in the game! I haven't used either because neither is really appropriate for the character build that I had used for the DLC.
Each of these weapons feels genuinely distinct from any of the base game's weapons. They don't just feel like stronger versions of existing weapons; they each play a little differently, and feel new. None of them has any genuinely new mechanics associated with them (except maybe the whirligig), but they all fill niche roles and add welcome variety to the types of offensive and defensive actions available to the player.
Almost would have paid for the weapons alone
I like The Old Hunters a lot. The new locations and bosses are good and tough, and the fancy new weapons are almost worth the purchase cost by themselves. It provides excellent supplements to the existing lore, blends perfectly with the base game's Lovecraftian influences, and the design of the levels, creatures, and new weapons just blows Artorias of the Abyss out of the water! My enthusiasm is a bit tempered by the esoteric entrance to the Hunter's Nightmare, by the lack of any really new mechanics or completely exotic enemies, and by the lackluster League covenant and questline (if you can even call it a "questline").
The Old Hunters also failed to execute two of my suggestions for improving Bloodborne. The DLC doesn't provide very good instructions on how to access its content (or make existing base game instructions any less vague), and if you miss the dialogue prompt, then good luck figuring it out! The Hunter's Nightmare itself is very generous with blood vial drops, but sorely lacks bullet drops, which can force the player to go back to previously-explored areas to farm. This is especially true since many of the old hunters that you'll be facing will be best handled by counter-parrying their attacks. Max vial and bullet storage has been increased by post-release patches, so as long as you've been stockpiling them before going into the DLC, you hopefully won't run into too much trouble.
Weaknesses aside, fans of Bloodborne should definitely pick the DLC up. Bloodborne is probably the best game available on the PS4, and having more Bloodborne to play (and fun new weapons) only makes it better.
"The Old Hunters" doesn't address my criticism that Bloodborne is poor at providing directions to the player.