Wait, didn't we already do a Fantastic Voyage parody?
Yeah -- it was Claptastic Voyage, when Borderlands last took us inside a party member's "mindscape." Surprisingly, Psycho Krieg and the Fantastic Fustercluck makes several of the same mistakes.
Its aesthetically-imaginative level designs look neat, but enemy behaviors and arena layouts are no different from what we've seen before. (I could only think of one truly-new enemy, the rocket-riding psycho, which is a fun idea but not interesting to fight.)
By focusing the story on one character, and not a very compelling one at that, it neglects two of the franchise's typical narrative strengths: wacky tertiary characters and comedic character interactions. (Krieg's "sane" inner-voice straight-manning himself just isn't enough to carry the tale.)
And, though less-so than Bounty of Blood, Fantastic Fustercluck similarly tries a little too hard for some "serious" story beats. Krieg's heartache over Maya is borderline creepy, and his tragic origin story turns out to be a familiar psychotic-break trope.
This DLC also has a shockingly difficult final boss battle, considering how easy the rest of its encounters were. (Though unlike in Claptastic Voyage, we did actually finish this one.) Here's a combat design suggestion: when character options heavily feature "Kill Skills," buffing the player after each kill, you probably shouldn't make a boss fight that has nothing to kill.
Fantastic Fustercluck has a couple of cool ideas, particularly the segments in which you're chasing - and being chased by - a psychedelic train called Locomobius. And, I mean, the core Borderlands shoot-and-loot gameplay still works just fine -- nothing wrong with that.
But it never really capitalizes on its ideas; including Locomobius, which just ends in a boss fight where you shoot at the train a bunch.
Better than: Borderlands 3: Bounty of Blood - A Fistful of Redemption, Borderlands: The Pre-Sequel - Claptastic Voyage
Not as good as: Borderlands 2: Sir Hammerlock vs. the Son of Crawmerax, Borderlands 3: Guns, Love and Tentacles - The Marriage of Wainwright & Hammerlock
Krieg's tragic science-experiment backstory: feels like it might have meant to hint at a broader "origins of the psychos" plot point; I'm not really sure why this DLC dug itself in so deep, there.