The idea is simple if you've ever played paintball you know the objective is you form a team and you take on the other team by shooting them with a paintball gun. The team that has the last player wins.
This just takes it up a notch with what is possible today to make it more challenging. Drones can fly autonomously and you can have a drone that's powerful enough to carry a small camera
so it also can carry a paintball gun. Assuming you can get through the legal paperwork of making drones that can fire paintball guns and assure legislators that this doesn't mean someone can rig it to carry a real gun and use it then you have a drone for your gaming arena.
You should theme it as "Man vs Machine" but that said here's how it would work. You'd need to train your drones to evade being shot and you can simply do that by designing a Machine Learning model that gets input from a camera that can swivel around. All it would need to do is identify a person holding the paintball gun and calculate the pointing direction of the gun's nozzle. If it's on the scope's sight it navigates away.
So you don't have to actually shoot at the drone during training and waste too many paintballs in the process all you need is an infrared laser and it would simply be avoiding the light pointing in its scope area. Linking this information of the gun's orientation with the infrared light is enough to train it on the probable trajectory of the paintball if you fire. With that you can train it well enough that it evades the laser well enough and now you can attempt to fire at it and see how well it evades. Also it would be a good idea to make the drone hydrophobic which means water or any water-based liquid won't stick to the surface. This makes it simpler to clean and also waterproof so the paint doesn't get inside and damage the electronics.
With that all you need to do is how to calculate a hit and with a gyroscope a sudden hit by a paintball will register as a sudden nudge in one direction. And that's all you need, the drone is now out of the game and will then fly away and you can now have a team of people vs a team of drones to see who's got the skills.