Created an Adventure mode:
Stage 1 - Mushroom Kingdom
It starts like Melee's but with more enemy variety. There are Goombas, Paragoombas, Koopas (Green and Red), Parakoopas (Green and Red, both flying and jumping), Spinys and there's one Lakitu that starts following you at a point. You then enter a pipe and gets in a cave. There are the same enemies here, but Goombas are blue, and there are Buzzy Beetles and Cannons shooting Bullet Bills. Then you get out of the cave with another pipe and enter Bowser's Castle. Now there are Dry Bones, Podoboos and Firebars. You also get damaged by falling in the lava. At the end you fight one of these posibilities:
Mario
Luigi
Peach
Bowser
Toad
Dr. Mario
Mario + Luigi
Mario + Peach
Mario + Toad
Luigi + Peach
Luigi + Toad
Luigi + Dr. Mario
Peach + Toad
Peach + Dr. Mario
Toad + Dr. Mario
Mario + Luigi + Peach
Mario + Peach + Toad
Mario + Luigi + Toad
Dr. Mario + Luigi + Peach
Dr. Mario + Peach + Toad
Dr. Mario + Luigi + Toad
Stage 2 - Green Greens
A Kirby stage. There are Waddle Dees, Waddle Doos, and Bronto Burts. At the middle of the stage, there's a fight with team Kirby, a team consisting of 10 Kirbys each with a copied ability of some playable character. You then play more and when you get to the end you must fight one of these posibilities:
Kirby
Meta Knight
King Dedede
Kirby + Meta Knight
Kirby + King Dedede
Meta Knight + King Dedede
Kirby + Meta Knight + King Dedede
Stage 3 - Hyrule
This stage plays old-school Zelda style, with top-view. You still have damage percentages, gets knocked back and everything you would expect in Smash, however. There are Octoroks, Redeads, Like Likes and other enemies. At a point you enter a dungeon and must solve puzzles. At the end you must fight one of these posibilities:
Link
Link + Zelda / Sheik
Link + Toon Link
Zelda / Sheik
Zelda / Sheik + Toon Link
Ganondorf
Link + Zelda / Sheik + Toon Link
Stage 4 - Yoshi's Island
A stage with Yoshi enemies like Shy Guys and some Mario enemies like Piranha Plants. At the middle of the stage, there's a fight with 9 super light Yoshis plus a giant Yoshi.
Stage 5 - Corneria
In this stage you are aways inside an Airwing. You can shoot with the attack button and fly. Wolfens fly in and try to shoot you. At the end you get out of your Airwing and must fight either one of these posibilities at the Corneria stage:
Fox
Falco
Wolf
Fox + Falco
Stage 6 - Brinstar
A stage with hot acid that damages you. There are Metroid enemies here. At the end, you must fight either Samus, Zero Suit Samus or Ridley. If you find a secret exit, you must escape via the Brinstar Scape Shaft. If you don't escape it fast enough, you lose a live. If you escape fast enough, you will see a strange portal. Enter it and you go to a secret stage.
Secret Stage - Super Flat World Arena
Here, you must fight Mr. Game and Watch. Defeat him to unlock him. I made this a secret stage because the only character from the series is unlockable, so it won't be spoiled to you if you don't find this exit.
Stage 7 - Archanea
A stage from Fire Emblem. Each time you encounter an enemy, you fight with him in a turn-based battle. He attacks, then you use one of your character's moves. At the end you fight either Marth, Ike or Chrom.
Stage 8 - Kanto
This Pokémon-themed stage features common Pokémon as enemies. If a trainer spots you, he sends one of the playable Pokémon (Pikachu, Jigglypuff, Squirtle, Ivysaur, Charizard, Mudkip, Grovyle, Blaziken, Meowth or Lucario) (except for Mewtwo) and you must defeat the Pokémon. You then get to Cerulean cave. The enemy Pokémon are more powerful here. At the end, you fight Mewtwo. If you find a secret exit, Mewtwo appears and transforms into Mega Mewtwo X / Mega Mewtwo Y and you must defeat him. A portal then appears, and if you enter it, you get to a secret stage.
Secret Stage 2 - Retro Place
A stage where you must climb a mountain and then fight the Ice Climbers. Then, your character is sent to a Ballon Fight stage and must defeat the enemies Ballon Fight-style, then fight Ballon Fighter in a normal battle. You then get sent to an arena to fight Takamaru. After this, R.O.B. appears, and defeating him makes him playable. This was made a secret stage because R.O.B. is the only character of his series and he is unlockable.
Stage 9 - Onett
You must go trought Onett fighting Runaway Dogs, Coil Snakes and Spiteful Crows. At the end you fight either Ninten, Ness or Lucas.
Stage 10 - Kongo Jungle
A stage where you must get to the end fighting Donkey Kong enemies. You find Rambi at a point and you may ride him. At the end you fight one of these possibilities:
DK
Diddy
Dixie
K. Rool
DK + Diddy
DK + Dixie
Diddy + Dixie
DK + Diddy + Dixie
Stage 11 - Pikmin Planet
You must get to the end fighting Pikmin enemies. At the end you fight Olimar.
Stage 12 - Skyworld
You must get to the end fighting Kid Icarus enemies. At the end you fight Pit, Palutena or both. If you find a secret portal, you get sent to a secret stage:
Secret Stage 3 - Third Party Stage
You must choose between the Metal Gear stage, the Sonic stage, the Megaman stage or the Pacman stage. You must get to the end of the stage fighting enemies from the series you choose and at the end you must fight Snake, Sonic, Megaman or Pacman depending what you have chosen before. Defeating the character unlocks it. Again, this was done because all these characters are the only ones of their series.
Stage 13 - Miscelaneous series
You must first get to the end of Smashville within the time limit while avoid the villagers, then fight the playable Villager. Then you get sent to the Wii Fit stage and must mimic Wii Fit Trainer's actions, then defeat her. Then, you must fight Mii. It will have the appearance of a random Mii from your console.
Stage 14 - The Final Fight
You must first win a 50-man Brawl. Then you fight Master Hand and Crazy Hand. Then Adventure mode ends.
Note: Some characters such as Mewtwo and Dr. Mario are unlockable, and may only be fought if unlocked. Below are the unlockable characters:
Dr. Mario
King K. Rool
Ganondorf
Toon Link
Ridley
Falco
Wolf
Lucario
Mewtwo
Ninten
Ike
R.O.B.
Mr. Game and Watch
Sonic
Snake
Pacman
Megaman
These unlockables, however, are fought even if not unlocked because defeating them is one of the ways to unlock them:
Mr. Game and Watch
R.O.B.
Sonic
Snake
Megaman
Pacman
I did not add bosses becase my "Perfect Smash Bros. Game" would have a story mode, and bosses would be used in it.