The Witness, the celebrated brain-melting puzzle game from Thekla Inc., is now available on iOS devices.

Thekla is selling the iOS version for $9.99 in the App Store — just one-fourth the price of the Mac, PlayStation 4, Windows PC and Xbox One versions, which cost $39.99. The Witness debuted on PC and PS4 in January 2016. It was released on Xbox One in September 2016, Nvidia Shield in January 2017 and Mac in March.

Thekla and lead designer Jonathan Blow have been planning to bring The Witness to iOS since at least as far back as October 2012, when Blow posted an image of an early build running on an iPad.

The iOS version appears to have the same content as the versions already available on other platforms, except with a touch-driven control scheme. Its low price is likely driven by the realities of the iOS gaming market, where the audience is trained to expect free games and $4.99 seems like asking a lot; remember how many people balked at paying $9.99 for Super Mario Run? (Comparatively, The Witness launched at $19.99 on Shield.)

The Witness’ arrival on iOS also heralds the debut of Apple’s revamped App Store, in time for the launch of iOS 11 this week. The store now offers a Today section with editorial content from Apple — it’s essentially a daily blog highlighting games and apps, with The Witness featured today.

In The Witness, you wake up on an island that’s completely deserted, with no sentient beings anywhere except for you. Everywhere you go, you find panels with line puzzles. There’s a mountain at one end of the island, and it seems like that’s your goal — but how do you get there? By solving hundreds of puzzles, of course. You’ll need to keep your wits about you, and use your senses of both sight and hearing, to learn the symbology of the puzzles and figure them out.

For more on The Witness, read our original review of the PC version, as well as our explanation of why it was one of our top 10 games of 2016.