I know your name is TrashGames but you have something here with a lot of potential!
Some ideas for this;
- Add sound fx when characters get hit by items which could be taken from the show. Example Gus's yell in that wheelchair scene
- Swap out the karts for mini cars like Mario Kart 8 did with the Mercedes dlc. Cars could be ones seen from the show
- Swap Items/Boxs to be more in theme with show. Examples, Bag of Blue Meth is the Red Mushroom,
- The Item Boxes model can be buckets of Los Pollos Hermanos
- Banana Peels can be pizza's ( like the one Walt throws on roof ) that cause the character to spinout when hit
- Cartoon Bomb can be pipebomb/C4 from wheelchair scene
- BlueShell/Missile can be a barrel of methylamine that rolls after the target
- Red/Green shells could have Tortugas head on it and say something funny as you throw it. The thing he says doesnt have to be from the show necessarily Danny has been in a ton of movies so theres lots to pick from