From the start, the cut-off pieces of moving platforms begin. Here, the player will find Eeries near the bottom of the platform from near the beginning. Later, the Fishin' Boo appears. The blue light of the Fishin' Boo can hit all the way down to the ground level. In the middle of the level, the player will find a ? Block (two in the Game Boy Advance remake) with power-ups, both of which either give a Mushroom, or a Cape Feather, depending on Mario or Luigi's status. At the end of the first room, the player will find another cut-off piece of the platform with a door nearby that takes the player to the next room. In the Game Boy Advance remake, there is a Midway Gate nearby as well.
In the next room, there are Boo Buddy Blocks. On top of the Gray Blocks is a power-up, which gives a Mushroom or a Fire Flower. The player will meet many train-like lines of Boo Buddies. To get to the exit, the player could perform spin jumps on the trailing Boo Buddies, or fly their way up to the door platform in the middle of the room with a Cape. The spin jump is only possible on the first of every line of Boo Buddies. Alternatively, the player could lure the Boo Buddy Blocks towards the edge of the platform where the exit is, and use them as platforms to jump up to the door platform. This door leads to the exit, and the player will gain access to Chocolate Island 2. If the player continues to the end of the room, they will find a dead end and a Rotating Block with a 1-Up Mushroom.