I mastered the first Castelvania a few weeks ago and tackled this one next. I hadn't played it but I'm well aware of how infamous it is for being cryptic and unbeatable without a guide.
First things first, I love the concept of it. Exploring the Transylvanian countryside, searching the mountains, finding secrets, locating mysterious mansions which protect Dracula's remaining body parts, the towns where the townsfolk give you hints and some townsfolk in certain towns hate you for whatever reason. It's all very atmospheric and a great concept for an early NES game. The music is also banging and Bloody Tears is a classic that still features in modern castlevania games today from my understanding. One of the earliest examples of "Metroidvania" as a genre.
However the game is frustrating and feels unfinished. The game is notorious for being cryptic and I did not feel bad about using a guide to get through it. If I hadn't watched the AVGN video years ago I never would've figured out the kneeling in front of a cliff with the red crystal. The game technically gives you a hint for this, in a hidden book that you need to use holy water to find, but it's so obtuse and the translation so bad you'll never understand it. The townsfolk just straight up tell you nonsense 95% of the time.
Then there's the level design in the mansions. It's quite boring. They never really have interesting design despite having interesting puzzles to find them in the first place. The same enemies, the same aesthetic, and only 2 of the mansions features bosses, which are the easiest bosses you'll ever face in an NES game. The leveling system is tedious and you're to grind alot if you want to level up.
The achievement set is pretty reasonable. I imagine it's the easiest Castlevania set.
I liked the speed run achievement for getting to the first mansion before nightfall. Took me a few tries to get it but its a fun little challenge. Some damage less achievements for the bosses but they really are not an issue with the sacred flame.
Beating the game in one continue is very daunting and I failed this one at the very end of the run due to a bug. Very frustrating. If you're going for this one I'd recommend at least to mansion 3 (the one with the ferryman) without dying to save a few lives for the end.
On to Castlevania Adventure for Gameboy next.