Pressing hard on the home screen icon reveals Quick Actions
One of the features that stand out on the iPhone 6S series is the 3D Touch. It's something you can immediately notice when you use the device for the first time because many of the stock apps take advantage of it. Basically, the phone's screen now knows how hard you push your finger against it, and translates it into triggering different functions.
In the home screen, a light touch on the app icon still launches it. But when you push it a bit harder, Quick Actions menu is triggered for the supported apps, letting you do get into various tasks even before the app is actually launched. It's something that I didn't know I wanted, but I would definitely miss it if it were gone. I'd be slightly frustrated to use older generation iPhones now thanks to this, sort of like how I feel about the lack of Touch ID on iPhone 5 and older. As it's the most obvious way that an app can be extended for 6S series, many of the 3rd party apps are now getting updated to enable this.
Here's a comparison video I made to show how 3D Touch lets you do more. On the left is an iPhone 6 Plus, and on the right is a 6S Plus. When I push the Photos app hard, 6S Plus shows the Quick Actions whereas 6 Plus only recognizes the long press and wants to know if I want to delete any apps.
Once into the app, pressing hard on a photo in 6S Plus lets me "peek", i.e. preview the photo, and if I push even harder, I "pop" into the photo and it's loaded on the screen. A light tapping feedback happens as I do this due to the Taptic Engine. On 6 Plus, nothing happens. This peek/pop interaction can be seen in many other stock apps, so I'm having fun trying to push the screen a lot to see there's anything more I can do.
A much worse case of cracked screen on my iPhone 6 Plus
Still looks bad while turned off
I had been using my iPhone 6 Plus with the repaired screen for a few weeks without issues. But one day, I put the phone down on the desk a bit hard... and the screen somehow cracked like crazy even though the screen was facing up. I suppose the previous incident weakened the screen already and this was sort of a final blow.
You can see that the cracks occurred near the original hairline cracks and spread dramatically. Much of the original cracks were held together by the glue, but the nearby areas were already vulnerable to crack anyway. While the touch screen functionality was not affected, the cracks undermined the safety of my fingers and the visibility. It was time to try the Screen Glue again.
I've cracked the back side of an iPhone when it was made of glass, but never the front side. That changed with iPhone 6 Plus - the screen got hairline cracks when the device was dropped from about 50cm (1 1/2 feet) high onto a brick road. Getting an iPhone bought overseas serviced by an Apple designated service center in Korea isn't possible due to local warranty (as opposed to world-wide), so I looked for other ways to get this fixed.
Screen Glue smartphone screen repair fluid
This is when I found this "Screen Glue" manufactured by DiYPRO which claimed to fix screen cracks by filling the gaps with a UV-curing glue. The package, which costs about US$17, comes with 5 ml of the glue and a sheet of instructions. Frankly, the price seemed steep for the amount of glue provided, but if it could get the job done, I thought it wasn't too bad. So I bought a bottle and got to work.