This should go in Worlds and Levels, and I was originally going to post it there, but I think it'd be better to start focusing all our ideas into one topic.
...then again, it'd get harder to read if the replies start piling up. But I didn't want to double post. In any case, if it shouldn't be here, move it there :<
Anyway, I'm going to crap out World ideas right now. Just to get things going a little bit. Not to say "USE THESE OR ELSE", of course, but to get the ball rolling.
Mario Bros. VersionWorld 1: Mushroom WayA simple world. Basic, generic "plains" level. to spice it up a bit, the first level could take place in Peach's courtyard or something. The Mario 64 rabbit could've stolen the half of the amulet Mario & Luigi had, and they must pursue him through a small level through the castle courtyard and maybe into Toad Town before he escapes. Then after they get it back they continue on their way through good old fashioned Goomba bopping stuff. Perhaps a few underground stages.
The boss is Petey Piranha at the end of the world. Petey's stage could be a pipe maze filled with piranha plants. Enemies here would be your basic grassland stuff, like Goombas, Koopas, Chain Chomps, perhaps, Piranha Plants...you know the works.
World 2: Bandito CanyonThis is a desert stage. The treasure the Bros. are looking for is in plain sight, but gets snatched up by thieves. I don't wanna push this idea too far, but I liked the idea of using Mask Koopas from SMW as bandits. So the level continues with Mario & Luigi pursuing the bandits to their hideout to reclaim the treasure.
Level ideas include a train stage, inspired by Kalimari Desert from Mario 64 or Dry Dry Mountain's train, where you chase the thieves across the roof of a speeding cargo train and have to rescue Toads from being robbed by them inside the train, a desert mountain stage with eagles, or, like the level from Sonic 2 on the Game Gear, a hang-glider stage where you fly over the Bandito Canyon itself. An oasis stage would be rather unique as well. Also, an ANGRY SUN LEVEL. Pleaaaaaase?
The boss fight would be inside a desert cavern level (think those cave levels with the Buzzy Beetles in SMB3) where you take on the boss of the thieves. If we use the Mask Koopa idea, I still have the MS Paint sketch for the giant Mask Koopa mech boss laying around.

I posted that in the boss topic.
The enemies here would be the thieves, Goombas, Pokeys, Lakitu perhaps throw in the Paragoombs with the little baby Goombas from SMB3, and...didn't Beezos show up in the desert world in SMB2? I dunno why, but I feel like they'd fit in there. (The little pitchfork wing guys.)
World 3: Goldrush MinesA gold mine stage. For ideas for visuals here, think Wario's Goldmines in Mario Kart Wii, or Team Fortress 2. I imagine it'd look something like that. The Wario Bros. would have this stage too, and you meet them as a mini-boss. Wario and Waluigi would be on the inner areas of the mines, with a mine cart stage a la Donkey Kong Country (which I'll elaborate on when I get to them), while Mario and Luigi explore the outer areas of the mines. High and mountainous, with a light desert setting towards the beginning to transition from the previous world.
The Bros. meet up about halfway and fight. After they fight, the two switch motifs, with the Wario Bros. exploring the exterior and the Mario Bros. exploring the interior. They both nab two separate treasures here. Mario and Luigi nab the treasure in an empty, untouched, underground room, seemingly unguarded...but then Phanto appears. He chases you for a bit and then ducks off-screen...and becomes a giant, horrifying Phanto boss. ...err, just an idea. Doesn't necessarily have to be used, and could go in other stages better, perhaps.
Enemies here that could work are Rex, the Mario 64 condors, Gnawtys from Donkey Kong Country, and Boos for some of the later levels for the Mario Bros. on the inside. The Miner Ant enemies from Super Mario Land 2 would be fitting here, given that...they're miners. Since they would be going deeper inside than Wario and Waluigi did, they'd be getting into darker areas. This stage would also be a good one to start employing new, made up enemies on--being that the Mario Bros. are starting to stray from their natural elements here.
World 4: Jive JungleA jungle area. Simple as that. I imagine it'd be a very tropical locale compared to the more foresty-looking jungles Donkey Kong Country used. It'd be simple to transition into from the last stage. We have the desert, the mountain with the goldmines, and on the other side of that mountain, a lush jungle. JUST LIKE REAL LIFE!
Levels could be your basic jungle areas, perhaps a lake stage inside the jungle's heart...things like that. Pretty simple. It'd be cool to have a stage like in New Super Mario Bros. where you would ride down a river on Dorrie the dinosaur, or perhaps substitute a raft for a more fast-paced version of this. Actually, dinosaur enemies would be cool here. Think Dino Dino Jungle from Double Dash. That was one of the best racetracks in Double Dash. Perhaps a stage where you climb across the top of the jungle and jump on dinosaur heads!
The boss here could be Birdo, whose diamond ring is the next treasure. PLOT TWIST! Since we already have a sprite for her, I think she could fit well here.
Like I said, dinosaurs are a great enemy for this stage. A lot of the enemies from World 4 of NSMB could be reused here, too, given the similar themes. Wigglers could go here, too, and the Scuttlebugs.
World 5: Koopa KingdomThe Bowser stage, and the second shared level. You know, this is personal preference, but I really liked how World 6-1 looked in the original Yoshi's Island. That was rather unique-looking compared to most other Bowser levels. But it'd still be good to use stuff like Valley of Bowser from SMW or New Super Mario Bros.'s last world to make it familiar.
It starts out with the same volcanic, barren wasteland type areas like in any other World 8. But then, Bowser sends his tanks out, and we'd have an auto-scrolling level as you jump across Monty Mole-ridden tanks, akin to SMB3. We'd later learn it was because Wario intruded the castle head-on. Realizing they can't get in easily with the heightened security, the Mario Bros. get in through an underground passageway and come up...through Bowser's toilet, and sneak into the castle.
They get into Bowser's throne room, and fight with Wario and Waluigi, who are still looking for the treasure. Bowser is at first entertained by their fighting, but after the fight, Bowser hears them talk about treasure and realizes they're going after his "new prized possession", and runs off. The Mario Bros. pursue him, while Wario and Waluigi decide to explore the castle with the Mario Bros. and Bowser both distracted.
The Mario Bros. chase Bowser onto an airship docked out back. Which takes off, of course, and you go through more sidescrolling delight. You reach the main cabin and fight Bowser for his treasure. After getting it, Bowser, in a fit of rage, pushes them out of his ship, and into the sea below. ...then realizing they took his new treasure with them, he sends his Toadies, as well as Koopas, down after him.
NSMB had some unique enemies in the final world, like those pumpkin headed guys, who I think would be interesting to reuse for the opening stages. Of course, we'd need Bowser's higher ranking fellows, like Hammer Bros. and Koopatrols...Bob-ombs, Monty Moles, Dry Bones...I liked those skeleton Pokeys from Mario & Luigi 2, too. Maybe they could work here. The bat-throwing vampire guys from Super Mario Land 2 would be cool too.
World 6: Yoshi's IslandThings go full-circle. The two brothers plummet down and land on a Yoshi's back down on Yoshi's Island. Conveniently, the next treasure is here. The Yoshi escorts the two through a few stages to the Yoshi village. The Yoshis owned their next treasure, but...it's been stolen by a frightful fellow who's occupied one of the abandoned castles that were formerly run by Kamek's stooges. The Yoshis will let the Bros. have it if they flush out this new enemy. It'd be Lakigeist, I think, who occupies the abandoned, now ghost house-esque castle, filled with other frightful enemies. Too scary for Yoshi to take you into, at least. (Akin to SMW.)
...to make this make sense, if we use the "call E. Gadd on the phone" idea, he could whip up a Yoshi translator for you to talk to the Yoshis.
Level ideas could include a stage made up of tons of Support Ghosts, a SMW-esque Banzai Bill stage, a Chain Chomp chase stage...
Enemies could include classic Yoshi's Island baddies like Goonies, Ravens, a few Shy Guys, Lantern Ghosts, the works. Bowser has sent Toadies after you, too. How poetic. And of course, we'd see his bipedal Koopas going after us. Or whichever it was we decided were "Bowser's Koopas" rather than generic Koopas. The ghost house final stage of the world would have all the unique ghostly enemies of Yoshi's Island, and Lakigeist at the end of it.
Yoshis would show up in the last two worlds after beating this stage.
World 7: Diamond CityThe next treasure is in Diamond City. The Yoshis lent you a little raft to get going on. The stages here would be inspired by the city stages in Mario Kart, and of course, Warioware itself. The Mario Bros. would take to the streets for most of this, passing landmarks of Diamond City and perhaps PIZZA DINOSAUR could be a mini-boss. I dunno. Then they realize the treasure is inside WarioWare Inc., and realize they can't get in so easy to Wario's home domain...so they decide to get in through the sewers.
...I guess that's trope we already used for the Koopa Kingdom, but the underground stages there would be more UNDERGROUND, and these would be more sewer-like. At the end of the last sewer stage, the Bros. get stuck in a situation much like the original Mario Bros., where they get accosted by Koopas and Sidesteppers. The brothers must clear out the screen of all of the enemies to be able to bring down the pipe into the WarioWare building.
Then in WarioWare Inc. itself, they have to take the elevator to the top floor. But the elevator stops at every floor. Great. So the Bros. must complete microgame-esque split-second tasks to survive each floor, before reaching the top, where they get to Wario's office, and his treasure pile.
The opposing Bros. serve as the main boss for this stage. Wario had found this treasure on a recent excursion, and stuffed it into his treasure pile. It just so happened to be significant. The winning team would get this treasure, and at this point it's a race to the final world.
Generic enemies here could include Fronks/Shags, and Bowser's ever persistent Koopas.
World 8: Ancient TempleThe final world. It's a race to the finish against the Wario Bros. as they pursue each other through a temple. Good inspirations for these stages would be the Angel Island/ Chaos Angel ruin levels from the Sonic Advance series, or the Ancient Ruins stages in Subspace Emissary. (I imagine that same tense Chaos Angel music for this level. That music was so epic but yet it was rather unfitting. Here it would fit that "ultimate race to the finish" feeling.)
It's simple enough to imagine. The same booby traps and stuff anyone would expect from a years-old temple. And difficult, too. It would start out outside the ruins before we get inside. Then, in the final stage, we meet Bowser again. While the previous battle was a straight-up clash with him, now he's breaking out the Koopa Clown Car. But I dunno how exactly we'd fight him--let's not make it exactly the same as before, of course. Then, Wario and Waluigi challenge the two brothers for an all-or-nothing fight for the treasure.
Enemies here would be things like Pokeys, the Anuboos from Mario & Luigi, more Boos again, those vampire kids again...Lantern guys...more Phantos...and it'd also be a great place to introduce original enemies. Oooh, how about the Broozers from NSMB? They were cool.
After beating the Wario Bros. this time, the Mario Bros. take the remaining treasure, and get...a room full of nothing. But if you've beaten both ends of the story, you'll find...
World XThe ancient spirit sucks the Mario and Wario Bros. into his domain. I think World X works just fine for the name. There's one final, difficult level for each pair of brothers one must go through before fighting the final boss. How we'd do this and how we'd design the last boss I'm sketchy on, but I imagine you'd have one form for each pair of brothers. Mario & Luigi fight the first form, but get knocked out, leaving Wario and Waluigi to take on his true form, perhaps. I dunno.
...and that's about as far as my ideas go. The ending and stuff I dunno about. I'd do something for the Wario Bros., but I am babbling forever right now and I'll wait to post that. For now, TELL ME WHAT YOU THINK.
tl;dr version:
World 1: Mushroom Way (Boss: Petey Piranha)
World 2: Bandito Canyon (Boss: Mask Koopa Mech)
World 3: Goldrush Mines (Boss: Big Phanto)
World 4: Jive Jungle (Boss: Birdo)
World 5: Koopa Kingdom (Boss: Bowser)
World 6: Yoshi's Island (Boss: Lakigeist)
World 7: Diamond City (Boss: Wario and Waluigi)
World 8: Ancient Temple (Boss: Bowser/Wario and Waluigi)
World X: World X (Final Boss: Ancient Spirit)
This post has been edited by Evang on May 10 2008, 07:16 PM