I watched that first 40 minute Famitsu video and a bit of a stream, and it seemed pretty easy.Only about 2-3 hours in so far, and this game just oozes with style and polish. Moving a bit slower than usual because of having to look up words here and there, but I've been surprised with how manageable the game has been with JLPT2/3 proficiency (although I'm generally stronger with kanji).
I guess if there's the mandatory godlike being monologue about human nature and the concept of reality in archaic Japanese it could get tougher, but I would think JLPT2/3 level Japanese with the occasional dictionary reference would get you through just fine.