They castle was basically a really big 1 story building. You didn't climb up stairs to get to the second floor. You went through a door. Metroid showed how to do this type of platforming world correctly...or at least better. Metroid Prime was still a bit too horizantal to me. ANYWAYS, one would have thought they would have fixed this in Curse of Darkness...WRONG! Instead they made the game so damn big it sucked even more. They really had no clue what people hated about the first game and it shows big time.