I recently bought 2 NES games:
My first VC was Mega Man II. I bought this one first, because many fans look at this game as the most popular one of the series. And I can't blame them. It's very good. So I bought Mega Man. I love it. I freaking love it. The music is very nice. The gameplay is fun and simple. But the game is very difficult. I passed the first stage with a big headache. I beat Cutman with frustration. And that's just one stage!
Castlevania. A franchise that is forgotten by many. I never played a single Castlevania game though. So I decided to buy this one. A lot of people find this game difficult. In the first two stages, I didn't had that much issues. Till stage three. I really REALLY got mad. I suddenly realised that I was busy with this stage for a week. And I still haven't beat stage four! It's because Simon jumps back. That's it. And the stiffness of the jumps. Overall: This game is very original in my opinion. The music is good and catchy. Not a bad game. But it really is a difficult. REALLY difficult.