It sure is. (* ^ ω ^)

I remember spending 4 hours straight to complete that Main Interlude in one go... _:(´ཀ`」 ∠):_

Yes, @Stray Bird It took me 5 hours to finish Interlude, but I decided to take a break, but I'll finish it tomorrow, to face the Beast IV: L, but now I don't know what will happen if I finish Tsunguska's Main Interlude, I think they are going to put on the Retrospective Battle to use Beast IV: L as a punching bag for Demonic Beast Servant, as happened in SERAPH.

You can't replay it, unless it's located somewhere I can't find. No great loss since this is one of the least fun battles in the game IMO (too many gimmicks to keep track of, most of which are incredibly cheap)

The gimmicks are quite good. It's definitely fun to do some solo or having fun with debuffs instead of buffs. Definitely not a cheap gimmick.