The best iPhone Duo apps to download on day one

There’s excitement around the launch of the iPhone Duo, as it’s the very first folding device that Apple has produced. That means a significant change from the single-screen design of iOS to an adaptive display that can switch between the smaller portrait front display and the large landscape format central display, and also factoring in the folding nature and the ability to offer multi-screen.

This has created an opportunity for app developers not seen since the launch of the iPad. While developers of legacy apps rush to offer fixes to make use of the new features and real estate, new apps are springing up even faster.

While some of these offer genuinely useful features brought about by the iPhone Duo’s design, others are just about having fun. It reminds me of the classic iBeer app for the iPhone, which uses the phone’s sensors to make it look like you were drinking a glass of beer as you tipped your phone up, or the augmented reality Star Walk app for the iPad, allowing you to identify stars and planets.

Below are four new apps that make the most of the new Duo screen that are worth trying. Plus some that haven’t made it to the App Store yet.

In the app store

1. Battlefleet Duo

The classic game of Battleships is brought to life in this app for a fun take that makes use of the folding display in almost a laptop-like position. The top half of the screen becomes your enemy's waters, showing where you've aimed, while the lower half shows your own fleet. You can also play it fully open, or on the outer screen, but that's not quite as fun.

Download Battlefleet Duo from the Apple App Store for free.

2. PianoFold

This tap-the-tiles-in-order game has hints of Guitar Hero and Beat Sabre, but it's designed especially for the iPhone Duo. With your Duo folded into a laptop-like position on a desk or surface, the top half augments the notes coming towards you in a highway arrangement. The bottom half becomes your piano keys, with four large coloured keys that must be pressed in time to match the oncoming notes.

Download PianoFold from the Apple App Store for free.

3. Foldhide

This app takes the virtual wallet to a new level by recreating a real leather bi-fold wallet. It's interactive in the fact that you can select each card to remove from the wallet and flip them around to see the back. You can also pull out the receipt and the banknote. By clicking on the pen, you can edit the cards to match your real accounts and store your details (just the last four numbers). It's a shame you can't then use the cards in here instead of the Apple Wallet, but that would require a lot more security. This is, after all, just a bit of fun.

Download Foldhide from the Apple App Store for free.

4. Deck-Man

Possibly the best new app we've seen so far, Deck-Man (originally Duo-Man) turns your iPhone Duo into an 80s-style portable cassette player, like the Sony Walkman. The great part of this app is that you can select music from your Apple Music library to play or from local files. You can use the pause, fast-forward and rewind buttons to skip through your tracks, all with mechanical clicks. On the central screen, you can see the cassette playing, while the outer screen shows the closed player, with a choice of designs. Occasionally, tapes will get tangled and need winding back in, just like the real thing. This is a must for your Duo.

Download Deck-Man from the Apple App Store for $4.99/£4.99.

5. Tesla

Though not specifically for the iPhone Duo, Tesla's updated app has native support for the larger screen, giving you almost like a split screen effect with the features down the left side and a large image on the right. It looks much more like the display you see in-car and will look excellent on either iPad or iPhone Duo.

Download the updated Tesla app from the Apple App Store from 23 October.

Coming soon (maybe)

6. CalibReader

One of the nice things about the NanoTexture display used for the centre screen on the iPhone Duo is that it's nicer for reading, and this app makes full use of that. The CalibReader app is coming soon to both Apple's App Store and the Google Play Store. It works for iPhone and iPad, but it's on the iPhone Duo where it really excels. It gives your phone a real book feel, with a clean full-screen layout, dark and light backgrounds and animated page curls as you turn a page. The outer screen gives you the book cover when closed, and when you open it again, it takes you straight to your page. You can import your own book library or link to your cloud storage, with pricing at $9.99 for lifetime use, or the first three books for free.

See more about CalibReader on its website.

7. Accorduon

I really hope this one makes the App Store. Accoduon, turns your iPhone Duo into a playable accordion. As with an accordion, your right hand plays the melody on the keyboard and the left hand plays the bass nots using the buttons. To make the sound, instead of squeezing you fold and unfold the device to push the air through the bellows. Pick a song from the list and it will guide you through the notes too. This could be a lot of fun.

8. Crate

Another musical app hoping to make it through to the App Store, Crate is an AI-powered music sampler. It uses a split-screen layout to divide the sample pads from the sequencer window, and uses the hinge to add special effects to the sounds. You can also use a text input to find the right samples and sounds to use.

9. TranslateCat

Another clever use of the dual display, TranslateCat is a two-sided interpreter, giving you the ability to type in one language at the bottom and see your translation at the top. Then, on the outer screen, your translation text is shown to whomever you're conversing with. Designed to work with eight languages, including English, French, Spanish, German, Japanese, Chinese, Korean and Portuguese, it's a neat idea. No hint of when or if it will go live right now, though.

Monster Ink

While this appears to be an 8-bit city builder game, it's actually a clever tool to stop you using your phone too much. The idea with Monster, Ink is that while your phone is closed the helper cats build the city for you, but open your phone up and the Kaiju cats start to tear it down. You get a warning when you peek at the inner screen, but look too long and things go downhill for the city. A really clever idea that I'd love to see make it to the App Store.