Attached to a wall at Ustwo Games' London studio is one of the team's favourite user reviews for Monument Valley.
It says: "Thank you for making this game, I thought it was really beautiful, one of the best things I've played on mobile, and it really impacted me. I just thought £3.99 was too much."
"That's always been super funny to us," chief creative officer Dan Gray tells GamesIndustry.biz.
Amusing as it is, it illustrates the biggest challenge of the mobile space: the value players place on games. Following the launch of the App Store, a race to the bottom means that the vast majority of mobile titles are now free-to-play..
Premium is still an option, of course, as Ustwo has demonstrated with Monument Valley -- the sequel to which made $10 million in its first year. But Gray acknowledges this is not the norm.
"Making premium games has been a dangerous proposition for a number of years," he says. "Even we know we were very lucky with Monument Valley. We were lucky to get a unicorn, but the exception doesn't prove the rule. It would still be dangerous for us now to throw a game out there and charge £5."
For Ustwo's newest release, the company is part of a larger experiment to see if a different model can prove just as successful: subscription.
The studio's new narrative puzzle game Assemble With Care challenges players to repair an assortment of objects, from cameras to music boxes, in a touching story about broken things and broken relationships. And rather than charging £3.99, it's available only through a subscription to the newly-launched Apple Arcade.
The new iOS service is Apple's latest venture to drive gaming on mobile without all the trappings of free-to-play. And, Gray tells us, it removes the concern raised by Ustwo's favourite user review.
"One of the things that's good about subscription in general is there's no direct one-for-one value transaction," he explains. "People are going to come and play Assemble With Care, they're going to have an amazing two hours... You might pick up Assemble With Care and decide it's not for you, but you won't feel like you've wasted any money. It unshackles the finances from the experience. I'm actually really excited about it."
"Subscription services mean different people can try out different things depending on what they want to do. That's really exciting"
Joel Beardshaw, Ustwo Games
It's interesting to note that Assemble With Care was not designed with subscription in mind. The prototype was first made early last year, before the conversation with Apple, and both Gray and lead designer Joel Beardshaw assure that the fact it's now in a subscription package has not influenced the design in any way.
The duo are also excited for the potential long-tail effect of a subscription service. While most games spike at launch then tail off, Gray suggests adoption of Apple Arcade games will be "a lot more organic" as users explore the service months, perhaps years after launch. He also reasons the early adopters are likely to be tech and games enthusiasts, but Arcade will then "propagate to friends, family, partners as they try to share experiences with them."
Beardshaw, meanwhile, points to the opportunities presented by parents subscribing for their children: "So many people I talk to about Apple Arcade are excited about their kids having a safe space where they're not going to get bugged about IAPs or weird adverts or things like that. But then if they're not a person who's interested in games, they'll still flick through the service and go, 'Is there anything for me?' and then find something like Assemble With Care."
Apple Arcade is also another viable outlet for developers making shorter experiences. Assemble With Care can be polished off in less than two hours, but that doesn't make it a less worthy addition to the service -- as Gray says: "You don't watch a six-episode series on Netflix and think that it's worse because there are 24-episode series out there."
"We think we do our best work when we make something that's beautiful, polished and short," he says. "Not going to get away from the fact that it's a short game, but movies are short. Movies aren't instantly improved by making them twice the length. A book isn't. It's this really weird game thing -- I understand that people want to get value out of the things they [play], and we're not being purposefully coy and holding back lots of stuff."
Beardshaw adds: "We're all very games literate people, so we're going to be going through way faster than the other half of the audience we're interested in: people who have never played games or haven't played since they were a kid. For them, to make a game that they can complete and see the whole story of, it's important that it's the right length for them."
This is something Ustwo has focused on since the original Monument Valley: 52% of the puzzler's players complete the game, with Gray suggesting it might be the first game some players have ever finished. But it was important to Ustwo to deliver the satisfaction of reaching the end.
"Particularly in a world of Minecrafts and other games that last forever," Beardshaw laughs.
Gray adds: "I always find it interesting that we don't have this conversation with other forms of media. I don't want to watch a six-hour version of Enter The Dragon and watch Bruce Lee beat more people up. It's great with the length it is."
It seems a strange turn of events that Ustwo, one of the few studios that found success with a premium game on mobile, has now ditched this model to be part of Apple's subscription service. It's not the first time, of course -- the original Monument Valley is already available in streaming subscription Hatch -- but it's certainly the first time Ustwo Games is debuting a new title without a price tag.
"It's always worth thinking about where the future's going," Gray explains. "You see everything that's coming out, the way everything is going -- and I'm saying this from the perspective of a developer -- everything is going multi-platform, it's going platform agnostic. There definitely has to be a future where... will there even be free-to-play, mobile only games? And then all premium games are multi-platform games?"
"Until recently, you either did a free game or a paid game and things were pretty static for a while. It's a really exciting time to be making games -- more than it would have been five years ago"
Dan Gray, Ustwo Games
Beardshaw adds: "Subscription services mean different people can try out different things depending on what they want to do. That's really exciting. And when you look at where Google Stadia is, the lines are blurring -- with Stadia, it's not going to matter whether you're playing on your phone or on your PC, it's going to look just as good.
"It's just about how you want to interact with it, where this game works well. I'm probably not going to play Assassin's Creed on my mobile because there are so many buttons to play. But for those games that sit somewhere in the middle, I've got those options."
The benefits of subscription for players are obvious, but there's still confusion as to how it benefits developers. For the moment, platform holders are (it's safe to assume) offering significant upfront payments to secure compelling content that will sell their new services, but as these become more crowded, will these payments decrease? In other mediums -- music, for example -- a 'pay per play' model has already made subscription almost unviable for independent creators. What does that mean for indie developers as the model becomes more prevalent in games?
Gray believes it's hard to predict for now, since any subscription service will look very different in five years' time. In this early stage, at least, comfort should be taken from the fact so many indies -- some of them with tiny teams -- are included in Apple Arcade. Having a platform holder actively reaching out to bring your game to their service "takes a lot of the risk out." And developers, especially indies, are being presented with more and more routes to market.
"Everyone's trying a lot of different things," he concludes. "Until recently, you either did a free game or a paid game and things were pretty static for a while. So from a design perspective and a commercial perspective, it's interesting that things are different.
"It's a really exciting time to be making games -- probably much more exciting for us as creators than it would have been five years ago."