As creativity and open-ended play continue to top children’s play trends, a new Liverpool, England-based company called Starship has developed a mobile game that’s fueled by a child’s imagination—and a console-worthy game engine.

Playworld Superheroes is a 3D-action adventure game for iOS devices with no in-app purchases. As the studio’s first app, it’s intended to help kids five and up design and then become their own superheros.

For an indie studio, the app has gained considerable traction since it launched on the Apple App Store worldwide two weeks ago. Within days of going live, it was in the top-five downloads for kids ages nine to 11 in the US and the UK App Store, and was featured in more than 65 countries.

“We know how difficult it is to be discovered on mobile and digital,” says Clemens Wangerin, managing director at Starship. “I think it’s a testament to the quality of what Playworld stands for, that it received that level of attention.”

Set in a city garden littered with junk, each chapter of the game starts in a treehouse, where kids literally craft their own superhero costume, painting and constructing it via their touchscreen devices. From the treehouse, kids use the “imagination cloud” to transform their creations and launch themselves into the realm of Playworld. They fly around the world and fight evil Golumites, jumping back to the treehouse to craft new tools and gadgets.

The cardboard-craft app is the brainchild of Starship founder Martin Kenwright, a 29-year industry vet known for starting Evolution Studio. Kenwright’s inspiration came from the juxtaposition of the real world and fantasy one, and the way children use their imagination to travel between the two quite easily. “Kids can pick up a cardboard box, put it on their head, and it becomes an astronaut helmet. They pick up a stick and it’s a sword,” notes Wangerin. “We encapsulated that in this piece of software.”

“We wanted the player to really feel like it was their character. Customization is a very powerful way of achieving that, because a player becomes invested in their creation,” Wangerin explains, noting that Playworld is almost a literal translation of how kids craft in the real world.

The arts & crafts focus serves a second purpose—Playworld also has an eco-conscious message that will appeal to parents. For instance, kids can take advantage of a rewards system, where they get points for correct recycling in the treehouse.

“It felt a natural extension for us,” says Wangerin. “The materials we were giving the players were found materials. They’re things that you would discard in your paper waste basket, or things you’d have leftover from wrapping Christmas presents.”

Along with its core moral messages, the app has lots of action for more gamer-oriented kids. As Starship’s founder (and most of its team) comes from a background in the video game industry, the studio was able to create console-quality graphics for the mobile app, using proprietary tech built on the Unity 3D game engine.

“We really wanted the whole thing to be an environment everyone felt is on par with spending time at the movies or having a really high quality entertainment experience,” notes Clemens Wangerin managing director at Starship.

And it’s working for the startup studio. Since the app went live, Wagarin notes feedback for Playworld has been positive, with many saying the original property had a fresh feel.

“It isn’t something they’ve already seen 15 times before because it’s yet another licensed IP that just has a nice looking free-to-play game around it,” says Wagarin. “It’s completely original. We know from outliers like Minecraft that building  and customizing your world is popular.”

As Playworld Superheroes continues to gain traction, Starship plans to launch more games in the mobile adventure series. Superoes is only the beginning in the Playworld series.

“We’ve picked superheroes as first theme, but you only have to look at children’s play behavior to know that it can apply to pretty much anything,” notes Wagarin.

“We don’t want to create a narrative-driven game, because we think the player will generate a narrative as they go through the different levels and they fill in the blanks. All we do is provide a certain setting.”