In Detail...
This level's graphics style is a mishmash of SMB3 with SMW. It's a sunken ship, so it mixes the SMB3 underwater tileset with the SMW sunken ghost ship tiles. I don't know shit about the palettes so I don't know if these SMW blocks are recolored to SMB3. We already start with two ? blocks, one with a powerup and the other with coins. There's a jellyfish up there, and some more ? blocks with coins. Swimming ahead we meet a Cheep Cheep and a Torpedo Ted blaster. There's a passage upwards with a yellow switch block. It deactivates a ! block column ahead. Right in front of the column, after you cross it, is another yellow switch block. The sunken ghost ship BGOs generate a cutoff here. Along the way you have to pay attention to the passages in the ceiling so you can find a blue switch block, and if you did hit that yellow switch block back there, you have to go back and hit it again to turn off the ! blocks so you can get a SMW star. We soon reach a door that leads to inside the sunken ship.
There's SMB3 underwater blocks inside the sunken ship. Here you just have to swim all the way up. It presents no real challenge until midway into the ship, when moving layers of spikes go around. You have to go all the way up to get to a door that leads you outside again. There's a checkpoint, but only the tape is there. The "blue candy" isn't there, so the checkpoint looks bad. We swim further, metting some underwater enemies, and when we meet moving spike layers, some Goombas are around. After this we swim further to go through another door that gets us inside the ship. This time we go down, and again the only real threat is the moving spike layers. The enemies are easy to avoid, you rarely use the Leaf and Flower powerups you catch along the way. We reach the bottom and go through another door, further inside the ship, and swim further on a large room until some wood appears behind us and we get this nicely-written (not) message:
"So Dumb Plumber I See You Manged To Make It To My Chamber But Unlike My Stupid Brothers Your Silly Jumps Or Stupid Flowers Wont Hurt Me Infact Jumping On Me Will Only Hurt Yourself So Prepare For Doom Ha Ha Ha Ha Ha"
"Ha Ha Ha Ha Ha" indeed. I guess the circumstances in which you fight this battle add a bit of challenge, but not much. You are underwater, making you slower, and there's Bill Blasters left and right. You defeat Iggy by grabbing the throwable bricks way high up and then taking them down to throw at him. Taking the bricks down to Iggy is boring, though. Iggy's blasts are unlikely to hit you, since you're swimming, until you try to throw a brick at him. Then the challenge goes a bit up, but not that much. We defeat Iggy, he says "Noooooooooooooo How Could You Defeat Me,Me Iggy Koopa The Mightest Of All Koopa Mark My Words You Will Die" (great dialogue!) and he leaves a star. End of level.
In General...
The mishmash of graphics doesn't bother that much, and the level has a nice maze feeling with the amount of passages leading to dead ends, but after the first sections the enemies don't pose much of a threat, and the boss fight's useless dialogue is cringeworthy. The worthlessness of the actual fight didn't bother me, but the dialogue is cliched and the grammar is awful.
Overall Rating: 5/10 stars
An average level. It started nicely but it got uninspired along the way.