A great climactic boss encounter feels a bit awkward standing alone.
For 9.99, you get one more chapter that is composed of two relatively brief levels. However, the difficulty is definitely higher than any previous chapter. Part of this is from frustrating platforming sections, but most is due to an extremely challenging boss which you battle in both levels.
The platforming is difficult; you have a sequence requiring speed as lava rises (similar to the gravedigger section in the original game). The opening of the second level has you hopping about lava rocks. The fixed camera generally worked fine for me throughout LOS, however this time I can't defend the placement, it made things much tougher than they should have been.
You get two small arena style combat sequences with enemies from LOS. At least for the skeletons, they set them on fire for a new aesthetic. Aside from these two encounters, the rest of the combat is focused on one hell of a boss fight.
I enjoy a nice difficult challenge as long as it is fair and the fight with the Forgotten One is great. To beat this demon on 'Paladin' is extremely difficult and equally rewarding to finally pull off. He has five stages, two of which you fight in the first level, the final three you face in the second level. He gains a few new moves the second time you fight him and his speed increases in the very final sequence. Each boss-stage is ended with a type of minigame that ranges from reflecting an attack back towards the boss, to throwing giant swords at him.
What makes it hard is that you can't just instant-win with ultimate combos. This was the biggest gripe most people had with the challenge factor of LOS. Once you got the ultimate abilities, nothing could stop you, not even the bosses. And of course now that the developers have taken that option away, the same people are whining that the game is cheap now. Damned if you do, damned if you don't.
The boss requires lots of patience and you actually have to learn his patterns and animations. Sort of how a boss fight is supposed to be right? If you go in just hacking and slashing (even on the easiest difficulty setting), you will die. With that said, he isn't that bad (play ninja gaiden if you don't believe me). I spent a good 2-3 hours total playing through once, and then going back for the trials and paladin completion.
The ending is shown in the comic style still-animations. Same as with Reverie - I'm not really a huge fan, but I don't dislike them either. The conclusion wasn't particularly satisfying, but I also didn't care for LOS's ending (not including the after-credits teaser).
Now what I didn't like overall with both of these DLCs is that they didn't exactly feel like they belonged in the game. You don't hear anything about the Forgotten One until the DLC, so there really is no build-up or sense of dread like what you feel during the LOS campaign. I also was not a huge fan of the 'look' of the Forgotten One. He appeared very similar to Pan's warrior form. Considering what the thing looked like in Lament of Innocence, I was hoping for something unique at least. This may have been intentional because Pan was some sort of 'Old God' and the forgotten one is also described as ancient. However, no references were made that I caught.
Another issue is that the chapter plays awkwardly on its own. You start it up and bam, huge epic boss fight, very, very little build-up. Now I haven't replayed any of the previous chapters recently so this might influence the overall feel.
My final complaint is that this expansion added nothing new outside of a difficult boss encounter and a few hide-and-seek platform sections. Reverie had a heavy dose of new puzzles and it also added a playable Laura. I'm sure I'm not the only one who was hoping to see Gabriel with some new moves especially when considering Reverie's ending. It was disappointing that they didn't continue in this direction.
The cost thing is subjective in my opinion. I covered this issue in my Reverie review so I won't repeat myself.
All in all this was a decent final chapter. I always like a game to end with the hardest fight, and The Forgotten One is by far, the most challenging encounter you will find in this Castlevania universe.
I hope the sequel expands on what has been a wonderful foundation.