I have some large ideas! The main game is sort of not a 3D game, but a 2.5D game. So, what about a 3D game? It wold be an open world game.
Runner: A well rounded melee character who moves fast normally. Unlocked at start. Weapon: Power Ram.
Gentleman: A healthy character who can use electromagnets to move faster and find Golden Power Shards easily. Unlocked by ramming all Dash Panels in Dark Mines. Weapon: Laser Crossbow.
Pastafarian: An intensely ranged but weak chracter who can nail an enemy from a long distance and do special effects. Unlocked in Stormy Desert. Weapon: Lasange wand.
Child: A high jumping but unhealthy character. He's great for far away platforms in jumping based area. Unlocked in Hot Hill. Weapon: Water Balloon.
Robot: A RAPIDLY firing and slow character. Can even make a Bomb to defeat multiple enemies. Unlocked in Electric Factory. Weapon: Mechatron Megashot.
Bat- First enemy found.
Ghostlet- Found in Dark Mines and Spooky Manor.
Burny- First found in Dark Mines as a light source.
Blue Burny- Boss of Dark Mines (Fought by Runner) and Hot Hill (Fought by the Pastafarian). Hit by only Flood switches being activated.
Cactpike- First found in Stormy Desert.
Sandstormer- First found in Stormy desert and the 5 near the Desert Cage must be defeated to unlock Pastafarian.
Cactoalie- Boss of Stormy Desert (fought by Gentleman) and Sport Danger (Fought by Robot). It homes on the player (in 2/3/4-player he moves to the closest player) so you can make it go in the Cactpike Crowd.
Warmer Burny- A damaging Burny in Hot hill. Only defeated by Water Balloons.
In-knight-er- 5 of these can be defeated to unlock the Child.
Burnstar- Mid-boss of Hot Hill. Fought by the Child.
Blue Burny Necro- Boss of Hot Hill. Just like the last battle against him, except he spawns in Ghostlets. Also, it's only weak when spawning Ghostlets.
Robat- An indestructible version of the Bat.
Batsplosion- Bats that rather use Bombs (which look like lemons) in Electric Factory. Only defeated by Lemon Bombs.
Twistit- A spining bat that guards the Robot's Crate as a mini-boss.
Bat-tron 5160- The boss of Electric Factory. Fought by the child, and must be defeated by Laser Tiles in a classic version of Run 3.
Pepphot- An enemy in Cooking Craze.
Cookit- A microwave enemy in Cooking Craze.
Fleabitter- An enemy in Cooking Craze that does Poison Damage. They're quite common in the area.
Chickook- The boss in Cooking Craze fought by the Robot.
Icer- An enemy in Icy City.
Freeeeeezer- A stronger version of an Icer.
Frosh- It's like you're fighting yourself! Fought by Runner, Just hit it 5 times and it's at the next phase.
Cactracer- Found in Sports Danger as a moving version of a Cactpike.
Cactpitcher- Throws spiky balls at the player.
Cactaoalie R- A tougher version of Cactoalie, fought by Gentleman. The crowd will also provide supportive effects to Cactoalie.
Megabat- The final boss! Every phase changes the character, starting with Runner. Jump in the cannon three times to go the next phase.
SuperMassiveBat- The TRUE final boss! it changes characters each phase. You have to get to the top, and jump on top of it to get to the next phase, and it is a heck of a climb.