"In the Pirates of the Caribbean Play Set for example, you play as a Pirates character, you have a pirate ship, you can sink other ships with it, you can get eaten by the Kraken," Day says.
"And you never take characters from outside and put them in that Play Set.
"Sulley from Monsters University stays out of the Play Set of Pirates, just as Jack Sparrow never goes to Monsters University."
He says the Toy Box is like the bedroom floor, meaning you can let your creativity run wild.
"You throw all your toys in there, build whatever you want, tell whatever story you want with any and all of the characters together," he says.
It sounds complicated, but Day says they have literally spent thousands of hours testing the game with groups of kids to make sure even the young gamers understand what's going on.
While Disney Infinity is mainly geared toward 7-15 year olds, Day's four-year-old son loves creating racetracks with his dad in the Toy Box and running around as Mr Incredible.
You can also buy additional characters to fit into the Play Sets and Toy Box, so while Lightning McQueen and Holley Shiftwell automatically come with the Cars Play Set, you can buy Tow Mater separately.
Day says when they launch, they're going to have about 17 playable characters from a variety of different universes.
"But moving forward we're going to continue to add more characters and more playsets," he says.
The freedom that Disney Infinity gives people is what makes it unique and potentially a new step in the future of gaming.
"Just to let people finally kind of do whatever their imagination leads them to do," Day says.
"I hope that's the future."
DISNEY INFINITY:
* Place physical toys onto the Infinity Base to launch characters onto the screen
* Explore the Play Set and Toy Box.
* In each Play Set, follow stories to unlock characters, vehicles, and gadgets, and save them for use in your Toy Box.
* Build your own virtual world in the Toy Box to save and share online.
* Collect 20 Power Discs to enhance environments and add gadgets.
* Monsters University, Cars, The Incredibles, Pirates of the Caribbean and The Lone Ranger will be the first available Play Sets, with more to come.
* Disney Infinity is available on all consoles in New Zealand on August 21 and costs $129.95.
