I had an idea for a SMW hack that I felt I just HAD to post. It would be similar in gameplay to Super Mario 3D World, and it would have a story where Peach actually doesn't get kidnapped.
The story: At the center of Star Road sits the Golden Star, which allows the Starmen to travel through space. One day, Bowser flys to Star Road with his armada of airships, destroys Star Road, and steals the Golden Star, in a attempt to stop the Starmen from coming to the Mushroom Kingdom to aid Mario. When Star Road breaks apart, some of the pieces are scattered across the Mushroom Kingdom, and the rest are scattered around space. Rosalina sees this happen, and visits Mario to tell him of this. After that, Mario and his friends set out on a quest to re-assemble Star Road.
There would be six playable characters, all accessable from the start of the game.
-Mario, who has the most well-rounded stats of the six.
-Luigi, who has a higher, floatier jump, but less traction.
-Toad, who is the fastest, with the most traction, but poor jumping skills.
-Peach, who is slightly slower than Mario, but can float using her dress.
-Rosalina, who doesn't jump as high normally, but can perform the spin move to attack and get a mid-air boost.
-Yoshi, who can use the flutter kick, eat enemies, and spit them out at other enemies.
Every time you enter a level, you get an option to change your character. Also, the 2-Player mode would not be turn-based, the two players can play the level at the same time. If one character dies, they have to wait for seven seconds before they get brought back into the level in a bubble, and if both players die before one respawns, they have to restart the level. Also, if one player is using Yoshi, the other can sit on Yoshi's back and jump off of him to get to greater heights more easily. However, the player riding Yoshi cannot control him, as the other player is controlling Yoshi.
The game would be based around finding the Green Stars, with extra levels being unlocked when you collect them. Castles, Airships, and some secret levels can't be played unless you have the required amount of Green Stars.
The game would have new power-ups, including the Ice Flower, Blue Shell, Tanooki Suit, Boomerang Flower, Cat Suit, and Mega Mushroom. The Starman would still be a power-up in the game, as some of them were in the Mushroom Kingdom prior to Bowser's attack. However, there would be no Yoshis in ? boxes, as Yoshi is already a playable character.
The game would have an inventory, and Toad Houses scattered across the overworld. There would also be slot machine levels unlockable, where you hit boxes to stop the slots. These levels lock up after you use them until you beat fifteen levels, or get a Game Over. The Super Tanooki Suit would be accessable if you die five times within a level, so that you don't get stuck at a certain level for forever.
Along with Green Stars is a collectable called a Power-up Coin, which looks like a Dragon Coin, but with a Mushroom on the front of it. One Power-up Coin is in each level. The coins are used for buying regenerating items. For example, if you buy a regenerating Super Mushroom, you will get an extra Mushroom in your inventory if you beat a level, die three times, or get a Game Over. This could prove useful during difficult levels. You can also only buy a regenerating power-up if you have gotten that power-up at least once.
There are new skills that the characters share. There is the Wall Jump, Long Jump, and Side Jump. there is also the Ground Pound, which shows where invisible blocks are for a split-second after you Ground Pound. It also allows you to break bricks if you are large.
After you defeat Bowser, Mario recovers the Golden Star, and Rosalina takes Mario and the others to space to find the rest of the Green Stars that didn't fall on the Mushroom Kingdom. you then can play through World Mushroom, World Flower, and World Star. After all of the Green Stars are found, Star Road is re-formed, appearing similar to how it does in SMW. You can then play ten more levels, all of which test all of the abilities that got you to this point, and you don't get to use the Super Tanooki Suit to make things easier. There are no Green Stars or Power-up Coins in Star Road.
After you beat the final level, Mario places the Golden Star in the Middle of Star Road, allowing the Starman to once again travel through space. You also get infinite power-ups in the inventory after you finish the final level, and a Super Tanooki Suit in the inventory if you can successfully beat every level in the game without relying on it.
Also, the SuperFX chip would be used for the Mega Mushroom to make the growing and shrinking animation smoother.