With the rise of free-to-play games in mobile, the death of premium-priced titles has long been foretold. But they seem to stick around regardless. And if the success of Monument Valley 2 is any indication, premium mobile games will be around for some time.

Today, developer Ustwo Games revealed that the sequel took in more than $10 million in its first year, topping the $5.8 million the original Monument Valley made in its initial 12 months. Premium games might not be the most lucrative games on mobile, especially when compared to free-to-play giants like Fortnite or Clash of Clans, but that doesn’t mean they can’t still make big money. “I think it has kind of plateaued,” Ustwo studio head Dan Gray says of the premium market. “It definitely hasn’t died, which is what everyone said every year for the past six years.”

Ustwo is unusually open with these kinds of figures, regularly releasing infographics that detail how its games performed. (That includes the games that don’t do as well as expected.) For Monument Valley 2, there are a number of interesting details to pull out. The game was more successful over those 12 months for a few reasons. First, there was the surprise launch onstage at Apple’s WWDC, which led to a big debut. Monument Valley 2 pulled in $728,000 on its launch day alone. It also had a global launch, which — most importantly — meant being available in China from the outset. China accounted for 62 percent of all Monument Valley 2 sales compared to 16 percent for the US, the next biggest market. The game also had the advantage of being a sequel, so millions of players already knew what to expect when it came out.

That success came at a cost, however. Monument Valley 2 was much more expensive than its predecessor to produce, with an estimated budget of $2.2 million. Part of that came down to the team size doubling from eight to 16, as well as increased marketing costs of more than $500,000. It’s also expensive to make a game in London, and those costs keep going up.

But much of the added cost was also due to the game itself. Monument Valley 2 was larger than the first game, with 14 chapters to play through compared to the original’s 10, and the team spent more time on visual polish. “We were obsessed with making the visual quality better than the first game, which means that we spent a lot more on design. We threw a lot more levels away that we weren’t happy with. We were definitely a lot more picky with the second game,” says Gray. “If we’re going to make successful premium games, they need to look and feel undeniably premium.”

While it has got off to a better start than the original, it might be hard to keep up that momentum. The first Monument Valley was actually more lucrative in its second year than its first, thanks to a confluence of factors, including a free promotion from Apple, a belated launch in China, and an unexpected feature on Netflix’s House of Cards. Those aren’t exactly things you can plan for with a sequel.

With Monument Valley 2, Ustwo tried to be a bit more methodical in its approach. It kept the game a secret until launch and partnered with Tencent early on to ensure a smooth Chinese debut. “You don’t just want to rely on word of mouth,” says Gray. “It’s great, Monument Valley 1 was a success because of word of mouth. But you would like to think that you have a bit more control over it, you can amplify it.”

Video game companies are typically very guarded about sales numbers, unless they’re boasting about new milestones. But for Ustwo these infographics have become something of an annual tradition. “It’s harder and harder to make successful, premium, paid mobile games,” says Gray. “So I would rather help people out.” He says that the community of premium mobile game developers is very communicative, sharing details like release dates ahead of time to avoid clashing with each other. “It’s kind of like this secret society of people trying to help each other out,” he says.

For Ustwo, the success of the Monument Valley series means a new degree of freedom. Creating a sequel to a beloved mobile game may have seemed like something of a sure thing, but whatever the studio does next likely won’t be such a safe bet.

“This is the time to take risks,” says Gray. “We’re fortunate. The game has done well. I’d like to use those finances to do some really risky projects that no one is taking risks on. Maybe talk about topics I don’t feel the games industry is talking about, try delivery methods that I don’t think are being done right now. These are the times we should be taking risks.”