Best NES / Famicom game

[ism22]

I'm generally a Sega man, but recently scored myself a Famicom and some games in Japan that I'm loving. My initial list of games includes some pretty common favourites (Mario 1, Mario 3, Zelda 1, Castlevania, Contra, Kirby, Samurai Pizza Cats, Ninja Gaiden and a few more).

Thus far Castlevania (in my case '悪魔城ドラキュラ') is my favourite as I love the music and exploration value. Haven't had enough time to connect with all the titles though as I'm flat out doing lotsa other stuff.

Any tips?