This is one long stage, and it's probably gonna be hellish if this is your first playthrough through it. However, it seems to have been made with Luigi in mind, and if find yourself comfortable with Luigi then it's not that bad at all. Just avoid falling through pits here, as they don't really cause instant death but rather make you drop several floors below, making you redo entire segments of the stage. Very annoying that.
Once you reach the end, you'll face off against the first truly challenging boss in the game, Robirdo. It takes a whopping 5 hits to take her down. She can attack by firing two giant eggs at you before trying to ram you with her massive body. She can also attack by stomping the ground, stunning you place for her to do that painful glomp of hers. If you're not using Luigi, you'll have to use the chains to avoid her charges. Luigi however can perfectly jump over her like nothing. Wait for her to fire them eggzookas before picking one up and smashing her face with it. Beware, she'll continue charging after the stun animation is over. Keep at it and she'll eventually fall.
