Kim Kardashian's game, "Kim Kardashian: Hollywood" has been criticized after children have racked up bills on the game.

The game may be free to download, but there are in-app purchases that can quickly add up. Kardashian guides people around Hollywood.

"You just have to make sure that your parental controls are all set," she said. "I think you just have to be responsible, and don't have your credit card linked to where your kid can just spend if they want to, or ask permission."

Kardashian said that even her sister has been making purchases in the game. She spent about $300 and called her to ask for cheats.

The game has also been seen as materialistic.

"In the game, you definitely see that it's just fun, and it's not really serious," she said. "It's just a fun little game, kind of like when people get into Candy Crush so much. Like, is it good to be obsessed with Candy? It's just something fun to do. All games, I think, are just entertaining."

The game is set to make $200 million by the end of the year.

The reality starlet has been surprised by the game's success.

"I didn't think it would do this well, and I wasn't underestimating it at all," she said. "But I'm really pleasantly surprised with how it's turned out."

Kardashian also spoke about her daughter, North West.

She described her daughter as not shy but that she shuts down when asked to perform. She also called her a "mama's girl."

Kardashian has also seen a change in Kanye West since becoming a dad.

Growing up with plenty of siblings, Kardashian loves the idea of having more children. But she had a difficult pregnancy. She plans to have one more child and then take it from there.