The app marks the first significant and officially sanctioned game emulator for the iPhone since Apple began allowing them, with wide-ranging console emulation from the original Nintendo Entertainment System to the Nintendo 64 (and even the Sega Genesis, for when you want to play those games that Nintendon’t).
Delta developer Riley Testut told The Verge via email that the app is identical to the version debuting with AltStore PAL. The app features on-screen buttons that change their layout and appearance to match whatever system you’re emulating.
It supports Bluetooth controllers like Xbox One Series S or PS5 controllers, too, and the app lets you customize their layout or set extra buttons for things like quick save states (essentially letting you pause a game whenever you want and load it up from that point later) or fast-forward through an old-school game’s all-too-often unskippable cutscenes or endless stream of startup logos.
Delta even works with some of the quirkier Nintendo input methods, like the gyroscope in WarioWare: Twisted! or the microphone controls in Nintendo DS games like Phoenix Wright: Ace Attorney (“OBJECTION!”).
Delta has other touches, too, such as automatically grabbing the box art for your games and the ability to customize that art using its built-in database or your own custom images, and users can import controller skins or make their own. It also supports multiplayer for the NES, SNES, and N64 (up to four players) as well as AirPlay streaming.
A small number of other emulators beat Delta to the punch, including one called iGBA that directly ripped off Testut’s GBA4iOS code and an NES emulator called Bimmy. Both were short-lived, though, with Apple taking down iGBA over spam and copyright App Store rule violations and Bimmy’s developer getting cold feet in light of Nintendo’s recent crackdown on emulators.
Notably, Testut’s app isn’t new. He released the 1.0 version of Delta in 2019 alongside the original AltStore alternative to jailbreaking. That means the app has already been through five years of feature and bug-fixing iterations, so it will likely be one of the most polished emulation experiences on the iPhone for a while.
Update April 17th, 2024, 12:45PM ET: Updated to reflect that Delta is now live on the App Store.