Mario's Adventure with Knuckles 4

Mario's Adventure with Knuckles 4 is the fourth installment in the Mario's Adventure with Knuckles series. It was created by P&F Games Inc. for the Nintendo Switch.

Story
Mario and Knuckles are busy taking a stroll through the Mushroom Kingdom when all of a sudden, Dr. Eggman comes down with his latest creation. With it, he plans to combine himself with Bowser to become the ultimate, unstoppable villain. But his machine malfunctions, and Mario's world combines with the Sonic world. Mario and Knuckles know they have to somehow separate the worlds, and also stop Bowser and Eggman. The two race off to see what their worlds have become.

Levels
The game plays as an RPG again. There are 8 (9 counting the bonus world) worlds in the game.
 * World 1: Grassy Hills (Mushroom Kingdom and Green Hill Zone)
 * World 2: Deserted Ruins (Layer-Cake Desert and Desert Ruins Zone)
 * World 3: Snowy Cap (Snowball Park and Ice Cap)
 * World 4: Cheep Cheep Coast (Sparkling Waters and Emerald Coast)
 * World 5: Giant Jungle (Soda Jungle and Green Forest)
 * World 6: Rocky Canyon (Rock-Candy Mines and Rail Canyon)
 * World 7: Cloudy Sanctuary (Rainbow Ride and Sky Sanctuary)
 * World 8: Industrial Volcano (Bowser's Lava Lake Keep and Final Fortress)

Mario Series

 * 1) Main Theme from Super Mario Bros.
 * 2) Underwater Theme from Super Mario Bros.
 * 3) Main Theme from Super Mario Bros. 2
 * 4) Main Theme from Super Mario Bros. 3
 * 5) Athletic Theme from Super Mario Bros. 3
 * 6) Main Theme from Super Mario World
 * 7) Fortress Boss from Super Mario World
 * 8) Bowser Road from Super Mario 64
 * 9) Slider from Super Mario 64
 * 10) Delfino Plaza from Super Mario Sunshine
 * 11) Baby Park from Mario Kart: Double Dash!!
 * 12) Coincentration from Super Mario 64 DS
 * 13) Luigi's Mansion from Mario Kart DS
 * 14) Athletic Theme from New Super Mario Bros.
 * 15) Comet Observatory from Super Mario Galaxy
 * 16) Gusty Garden Galaxy from Super Mario Galaxy
 * 17) Coconut Mall from Mario Kart Wii
 * 18) Wario's Gold Mine from Mario Kart Wii
 * 19) Title Theme from New Super Mario Bros. Wii
 * 20) Puzzle Plank Galaxy from Super Mario Galaxy 2
 * 21) Castle from Super Mario 3D Land
 * 22) Daisy Hills from Mario Kart 7
 * 23) Pandemonium from Mario Party 9
 * 24) Credits from New Super Mario Bros. 2
 * 25) Main Theme from New Super Mario Bros. U
 * 26) Double Cherry Pass from Super Mario 3D World
 * 27) Mario Kart Stadium from Mario Kart 8
 * 28) Main Theme from Yoshi's Woolly World
 * 29) Title Theme from Super Mario Maker
 * 30) Jump Up, Super Star! from Super Mario Odyssey

Sonic Series

 * 1) Marble Zone from Sonic the Hedgehog
 * 2) Casino Night Zone from Sonic the Hedgehog 2
 * 3) Palm Tree Panic from Sonic CD
 * 4) Hydrocity Zone from Sonic the Hedgehog 3
 * 5) Mushroom Hill Zone from Sonic and Knuckles
 * 6) Windy and Ripply... for Emerald Coast from Sonic Adventure
 * 7) Neo Green Hill Zone from Sonic Advance
 * 8) Metal Harbor from Sonic Adventure 2