The problem is that it was apparently designed in a vacuum. The problem with Curse of Darkness isn't necessarily that it's a bad game. This one area is not a huge section of the game, but it does reveal one thing - the designers simply didn't learn their lesson. Castlevania fans will remember Harmony of Dissonance, and its asinine 'collect furniture!' subquest, wherein you'd go out of your way to some part of the castle and end up getting rewarded with a completely useless set of drawers. I had wasted maybe twenty minutes for, for all intents and purposes, nothing. At this point, over halfway through the game, I only had two accessories total, neither of which were remotely useful. After slogging through it - you can't leave once you enter - I got to the top and got some item that allowed me to equip three accessories instead of two. The Tower of Eternity is entirely serious. I was, of course, completely fooling myself. Maybe the designers had realized this, and were parodying themselves?
Castlevania: Lament of Innocence was a decent game, but it's biggest failing was the insanely repetitive level design. It is fifty floors, which means you go through fifty identical rooms, fighting enemies over and over. At some point in Castlevania: Curse of Darkness, there's a stage called the Tower of Eternity.