This thing even greets you with the words "fun made product".

Firstly, the engine and core are the same, so you have rhythm jumping, pleasant 150 FOV, climbing, shortcuts for shotgun and stakegun and the game looks good and clean (that is, in the places where devs used textures and not blurry placeholders).
But it runs very poorly and has its share of bugs and crashes. When i reached haunted city it wouldn't load the level and i would just fall down into grey abyss. Fortunately, i forgot about it and when i launched the game next time it actually did load.
Next, the level design. It's an absolutely nonsensical mess, which would be somewhat fine if it wasn't stripping the player from progression agency. The levels are giant and long, but still, there are only 6-7 of them and they all poorly designed and balanced. It's a collection of narrow corridors assembled into giant labyrinths, while original had chain of fun medium sized arenas.
A lot of new enemies are just meat blobs. New weapon is a stakegun, again. I understand that stakegun is a iconic titular weapon of the franchise, but we already have it. And second one in BOOH. And an overdosed crossbow.
The worst part of it (yes, even worse than bugs) is the balance. It's a very short thing made by amateurs, so it's extremely difficult even on easy. Outside of high damage, there are immortal ghost which chase you and steal your HP. You can as well just give up and play on "story mode" difficulty, and even then you will be short on ammo on some levels. And with it you lose the second half of the gameplay — achievement hunting, gold management and tarrot cards.
Story is pretty generic, is told in lazy comics and has three endings, but no clear way towards any of them; and i can't even find any information on them. Barks of the protagonist are better than silence, but done poorly and get old very fast.

Well it's a bad one but it is doable. If you can more easily tolerate bad new experience than good but trivial ones — it exists.