Here's my concept for the next South Park game.

South Park: Revenge of the Cis.

It's Sci Fi based.

The Mall is having it's grand reopening, and to commemorate the event they are hosting a Sci Fi convention and giving away free Okama Game Sphere Pros with VR headsets to the team of 5 that wins a costume contest at the end of the convention. Cartman, over-excited, quickly forms his team with Stan, Kyle and Kenny, he's about to choose Kevin, but then the New Kid shows up, and Cartman makes him his "number one" AKA *****, and makes Kevin give him his Spock ears and uniform. (which sows the seeds of hate into Kevin like Clyde back in the Stick of Truth.)

The town heads to the Mall, where thousands of nerds are already swarming.The boys push their way through the crowd and into the mall to try to see the new Game Spheres. Cartman prances up to the stage where the consoles are being held in locked cases, and just when the rest of the boys reach him, there's a loud explosion from the back of the mall, thousands scream and panic as the mall's security gate close one by one, the crowd stuck inside starts fighting with each other. The boys manage to take refuge inside the Think Geek store before it's security gate closes.

They don't know how long they'll stay trapped in there,and start to argue, but they can all agree that the Think Geek store had the most awful interior design set up, and Cartman tells the New Kid to redecorate it. (which starts a tutorial on redecorating and claiming the area as their base of operations, new furniture and building items can be unlocked for bases later, the items are sci fi based.)

A main aspect of the game is weapon crafting using a forging station that's unlocked a little bit later. The new kid uses it by sticking a hose up their butt and endues their fart power into crystals that can be switched in and out of weapons, like phasers or light sabers.

Part of the story, is that the New Kid and the boys, must go around the mall saving other kids, gathering more to their army, and capturing other stores as their strongholds.

There are light side and dark side based classes, some examples;

Time Doctor (Dr. Who) has time based powers, uses a phone booth to call another, yet different looking version of themselves to come and help out, and a powerful laser blast screwdriver.

Captain (Star Trek) a summoner class that can send red shirted kids out to die for them, can unlock an Orbital Strike, and can use phaser type weapons that stun.

Space Monk (Jedi) a warrior monk based class that wields a light saber, can heal and push enemies back using their chi

80's puffy jacket kid (Marty Mcfly) (Maybe Stan's class) wields a hover board, can dodge enemy attacks with help from an almanac from the future, and can summon his grandpa to hit and run enemies with his Delorean and drive off leaving flames causing burn damage.

Dark Side

Space Warrior (Klingon) an alien warrior that uses a curved blade

Emo with anger issues (Sith) uses scream and yell abilities to push back or cause enemies to become nauseous and puke, also has lightning attacks, wields a light saber.