The ZenFone 5 runs on Android 8.0 with ASUS' ZenUI on top of it. ASUS has cut back on its own apps, and you'll no longer find duplicate versions of the browser, email, keyboard, or messaging apps that ASUS used to pre-install. There's no button for the app drawer, but you can access it by swiping up from the home screen.
As with most ASUS phones, there are quite a lot of pre-installed software features. There's a Face Unlock option, which, just like the iPhone X, can be used with a raise to wake gesture. ASUS's version of Face Unlock simply takes a picture of you during setup and compares it when you're unlocking your phone. It unlocks quite fast, but only really works in well-lit environments. I wasn't able to fool Face Unlock with a picture of me, but it's still not secure enough to use with any biometric payments, so it's really just for convenience.
There's also an AI ringtone option, which is really pushing the limits of what you can call AI, as it just automatically adjusts the loudness of the ringtone depending on whether you’re in a quiet or loud environment.
There's also a Twin Apps option, which we've seen on a number of other Android phones, which lets you create a second version of an app so you can manage two accounts at the same time. There's also something called OptiFlex, which apparently speeds up the startup of selected apps, although I didn't really notice it doing anything.
Finally, there's ZeniMoji, which as you can probably guess, is ASUS' version of Apple's Animoji, allowing you to use your own facial expressions to animate cute avatars.
ASUS uses a combination of 52 different expressions to mimic yours, and it can also be used in video calls or live streams on social media. Here's a video from ASUS to get more acquainted:-
Obviously, the phone doesn't have the iPhone X's 3D depth-sensing camera, so instead it uses an algorithm trained on hundreds of thousands of 2D faces with different expressions, lighting conditions, and angles. The algorithm then makes use of this data to approximate a 3D model of your face.
It sort of works, but is quite limited in application. If you smile, your ZeniMoji will smile, but it's nowhere near the 1-to-1 capture you get with Animoji.