Tubular - This is hard as hell the first time, but I know when to dip, when to let the P-balloon float (we can only thank God that, unlike Kuribo's Shoe, the P-balloon didn't come back in future Mario games...unless it did, gawd I hope not) so if I played it right now, I'd probably beat it on the first try, BRAG.
Way Cool - Oh goodie, a stupid "take the right lift" level. Fly through this f***ing thing somehow, either the cape or Yoshi Wings. Not because it's hard but because it's STUPID!
Awesome - If you're not cheating like a puss and flying through this icy level, the part at the end with the flying fish and disappearing stuff is actually reasonably hard.
Groovy - The level you see Mario self-playing on the title screen. DERP!!! Easy as hell. F***ing Star Road 1 is harder than this!
Mondo - A not very difficult level full of huge rising oceans. Boring.
Outrgaeous - Another level I'm guilty of just often flying through, if you stay on the ground it's admittedly a bit daunting.
Funky - The only level in the game with Green Apples for Yoshi to eat, they put 20 seconds on the clock along with a satisfying "bing!" sound effect. At the end is YOU ARE A SUPER PLAYER in big coins, I OCD'd getting all the coins. Was cooler at the end of Lost Levels world 9-4 which is just you swimming over a bunch of enemies that shouldn't be underwater and a message in Japanese spelled out in the blocks.
The end of the ocean world map, World 3, in Super Mario Bros. 3 is an island shaped like Japan, with the "HELP" castle where Kyoto should be, which I didn't know until yesterday.