Twelve months ago, Doug Heder found himself answering the same question over and over again. It went like this: "How the hell does this work?"
A year on from the release of Lego Dimensions, which combines comical video game versions of popular movie and TV franchises with real life toys that get placed on a game pad, Heder is finding life a little easier.
"It's much easier to demo ... my job's a lot more fun," he says. "We can really get to the stuff that makes Lego Dimensions so much fun, the little Easter eggs, those little mash-up moments, the surprises we like to throw into our games."
Heder, a game producer at Warner Bros Interactive Entertainment, is one of the guys behind Lego Dimensions, which has already released add-on packs based around Doctor Who, The Simpsons, Back to the Future and Portal 2.
But Heder's about to make Christmas much more expensive for fans of the franchise, with a whole new wave of packs hitting shelves, from the all-female Ghostbusters reboot, to Mission: Impossible, Gremlins and Fantastic Beasts and Where to Find Them.
Heder admits there are passionate office debates about which franchises should be added to the Lego Dimensions "family".
"We're out researching, we're looking at the film slate for each year, we see what's going to hit and we try to do our best to predict what will translate best into Lego form," he says.
"We've got artists and designers and programmers who shoot their hands in the air and say, 'Oh, I've always wanted to work on Adventure Time or Goonies, let us go do that one'."
Heder says the latest waves are better value for money. Ghostbusters includes an entirely new portal that can be built and placed on the game pad, as well as a full game experience, while Mission: Impossible comes with an Ethan Hunt figurine, two vehicles and a game based on the entire original 1996 movie.
It's had rave reviews - and rightly so. Challenges are harder and more complicated, players get to re-live the film's iconic scenes, and in jokes are more ingrained.
At one point, players have to play a jaunty piano version of the M:I theme song, then bash the piano down into blocks to rebuild it into a quick change costume machine.
"This is pretty cool, this one caught a lot of people by surprise," says Heder. "We're telling the original 1996 film. You're getting the film that started all this and the coming of age story of Ethan Hunt."
The most controversial decision so far - to include a level based around British time lord Doctor Who - also turned out to be one of the best.
"We had to do a little bit of convincing to the Americans in our department why it was so cool and why it would work," Heder says. "We were so happy we did it. It was a huge success, a great pack, so much fun."
There's one problem Heder and his team haven't quite been able to solve: teaching kids to keep their Lego Dimensions sets separate from their sprawling collection of normal Lego blocks. He doesn't see it as an issue.
"We encourage kids to mix and match. Something we really hoped would happen is fans catching the spirit of, 'Hey, we supply these bricks, we supply one instruction model, but there's nothing stopping you from using your own imagination and creating what you create," Heder says.
"Seeing that happen is really satisfying and pleasing. Seeing how fans treasure these mini-figures is really cool."
What: Lego Dimensions
Where and when: Ghostbusters and Mission: Impossible are out now; Gremlins and Fantastic Beasts and Where To Find Them is due out on November 18, and The Lego Batman Movie is due out in February.
Platforms: Playstation 3 & 4, Xbox 360 & Xbox One, Wii U.