A well done port of the NES classic, difficulty and all.
Now the game is broken down to two actions: jump and attack. You have the occasional sub-weapon such as the Axe, Cross, and everyone's favorite: the Holy Water. The Holy Water sub-weapon makes the game really easy, especially most of the boss fights.
However, the game is still very challenging. The difficulty curve spikes once you reach the later stages, most notably in the last 2 sections of the castle. It can get frustrating, but at least it's not Ninja Gaiden frustrating. One of my problems with the game is that in the later stages, enemies tend to deal more damage to you. The same enemies that you faced in the earlier levels tend to do more damage to you in the end. Basically damage is based on what level you are on, not which type of enemy hit you. That can get a little annoying.
To help make the game more accessible, the GBA version has added a save function, which I don't believe was in the NES version. Back then you had to finish this game in one sitting. So the save function in this game adds to the portability of the GBA – a nice touch for a handheld game.
One of the things that disappointed me in this game is the end credits. I was surprised to see the credits being different than the NES version. The ending was the same, but the ending credits were different. It's minute, but still I missed the misspelling of Simon Belmont's name.
Despite the difficulty curve, the game is very enjoyable – especially if you like challenges. When I finally finished the game, I felt a sense of satisfaction that I had not felt in a long time. If you are a Castlevania fan, then you owe it to yourselves to experience its roots – but be forewarned, you will get frustrated.