[update: 3/1/2021] The website is no longer live and must instead be viewed via "Wayback Machine" or other similar service. Luckily, the site was archived https://web.archive.org/web/20190319021555/http://tengaimakyouzero.g2.xrea.com/tengaizero.html

http://tengaimakyouzero.g2.xrea.com/

Nearly exhaustive resource for the game.
Contains detailed info on festival specifics. Enemy and boss statistical data as well as boss AI patterns. Item/equipment effects, prices, obtainable locations.

I think the only info I wanted that I was unable to find on the site is the sell value of the four elemental absorb bracelets, which is oddly absent from the accessory list (they sell for 1 Ryo, and not for 1/2 the purchase cost like normal)

Some notes when using Google Translate to view the page: One of the item shops is sometimes translated as "Miller" and sometimes as "Powder Shop". they're the same shop "Both" is money "squid increase" and "squid down" refer to changes in your Cool stat. A stat which only determines which splash art is used when your character uses a special move.