Nocturne has some dated design choices--too much backtracking, and some arbitrary traps--but there's more than enough good to make up for it. One of the much later areas, the Tokyo Diet building, has some fascinating visual elements I've not really seen attempted elsewhere.
One suggestion I make very strongly, though: do not try to "game" the philosophical decisions you'll be tasked with occasionally. Use FAQs or GAF advice to help with battles, fusion, party makeup, sure. But don't even read comments about other people's story choices! Just give real answers, based on what you actually think. This greatly improves the power of the narrative and the way things play out.