I recently finished Castlevania: The Adventure, and enjoyed it a lot. I think it's a great game, despite what others have to say about it. Anyway, what REALLY stood out to me was the fact that it wasn't all just fighting enemies like more recent Castlevania titles. There were some extremely fun, yet challenging obstacles besides enemies. For instance, the best example of this was stage three. Starting the stage, there is a long hallway, in which the ceiling is lined with spikes. After a few seconds of walking down this hallway, the ceiling begins to lower, in an attempt to crush Christopher. What you have to do is go down the hallway as quickly as possible (With Christopher, that's not very fast!

) ducking under indentations in the ceiling and breaking giant screws to make the ceiling rise. Then, once you think it's over, you make it into the next room and the floor begins to rise, and, as expected, there are spikes on that too! After climbing up a ton of ropes, taking out numerous enemies, and making some incredibly risky jumps, you make it to the stage's final obstacle. The wall (with spikes) on the right side of the room slides left across the room. Your only option is to head across the room in a race against time through numerous obstacles like ropes and falling platforms and make it to the end of the level before the wall crushes you.
Once I finished the stage, I thought, "Holy crap, that was insane! Why don't recent Castlevania games have that kind of stuff?!"
Really, why don't they? It's been all enemies with few jumps and platforming. And it's not just that one level; the entire GAME was full of falling platforms and moving spikes that seem to have been lost to past Castlevania titles. I think it adds more platformer elements that take away from the RPG elements making for a more enjoyable playing experience.