Photography plays a greater role this time around. You're getting a larger, 16-megapixel sensor with an extra-bright f/1.8 aperture and second-generation optical image stabilization -- much better for low-light situations, LG says. On the front, you'll see an 8-megapixel camera with improved gesture control that lets you take multiple selfies in one go. There's also a manual mode, RAW shooting and a color spectrum sensor that makes sure that your rear camera's photos are truer to life than before.
Performance-wise, LG is making the unusual choice of going with a six-core Snapdragon 808 processor, not the 810 you've seen in the HTC One M9 and other devices released early this year. The firm insists that the 808 is competitive with the eight-core Exynos chip in Samsung's Galaxy S6, however, and it's keen to tout battery life that should last you through a typical day. Moreover, the 3,000mAh battery pack is still removable -- you can swap out for a fresh unit if your charge is running out, unlike your S6-toting friends. There's likewise a microSD slot in case the 32GB of built-in storage isn't enough.
The company's latest take on Android (Lollipop, to be exact) will be familiar if you've used the G Flex2, but there are a number of noteworthy tweaks. A smart widget will tell you when apps are draining power while the screen is off, and SmartBulletin shows both app notifications and information in one place. There's a redesigned gallery app, as well. And did we mention that LG is keen to talk up partnerships? you get 100GB of free Google Drive space for two years just for buying the G4, and there's MirrorLink support if you're driving a Volkswagen.
LG was mum on availability at the event, but we'd expect the G4 to launch soon at typical high-end phone pricing. In the US, that usually means paying $200 on contract.
Update: AT&T, Sprint, T-Mobile, US Cellular and Verizon have all pledged to offer the G4 this spring. They're not talking prices yet, but Sprint and US Cellular have narrowed the release down to June.
James Trew contributed to this report.