It is a tough game. I beat it without a guide but man, my parents were mad when they discovered I used one of my spiral notebooks for keeping notes. This was back when school supplies ran out - there never seemed to be enough for everyone that needed them (and I was young so I didn't realize why they were mad back then).
I had played the first Castlevania and did alright in it but was not a big fan of it. I borrowed Simon's Quest in a trade with a friend and ended up buying my own copy.
It was such a unique experience - day and night cycle, the way the cities change, the exploration element, etc. For me, prior to Castlevania II I had only really played games like Super Mario Bros where you only could go one way. There was no real exploration and backtracking to see what you missed. There was no real puzzle solving either in games like Super Mario Bros.
RE: Castlevania II Simon’s Quest Branches Franchise on Nintendo NES – December 1st, 1988 – Today in Video Game History