Google's Dave Burke was keen to emphasize that the update was focused on small but significant improvements. Developers can now create smoother links between apps, for example, so tapping on a tweet in an email opens Twitter automatically. Coders can also take advantage of new Chrome Custom Tabs, browsing tabs that stay within an app (like Twitter) but bring all the benefits of Chrome (such as passwords and history).
With Android M, app permissions are going to become more iOS-like. Access to location, the camera, contacts and other elements isn't granted when the app is installed, but the first time these permissions are needed. After that, they can be toggled on or off from inside Android's settings.
Android M will also come with Android Pay, which Google had previously hinted at, and it's ready to go in over 700,000 stores in the U.S. from today. There are partnerships with AT&T, Verizon and T-Mobile, and it covers payments inside apps as well as NFC payments in stores.
Tying into that is the new fingerprint sensor technology built right into Android M, something that had previously been left to manufacturers such as Samsung to add on top. It's very much Google's version of Touch ID, and it will let you authorize purchases from the Play Store as well as unlock your phone.
Finally, Google had some power and charging news to share. Android M will bring with it a new feature called Doze, which recognizes when your device isn't being used and sends it into a deeper sleep. According to Google, phones or tablets can last up to twice as long with Doze enabled. The new OS also supports devices with the USB Type-C socket we have already seen in Apple's new MacBook.
There are smaller tweaks too: Simplified volume controls, a sharing widget that identifies the people you share with most often, improved word selection. In general, though, this is a much smaller step forward than Android Lollipop was.
Google Now is getting some extra smarts too. A new feature called Now on Tap better integrates Google Now with other apps - with one tap it can recognize content inside an email app or chat app and make reminders or bring up relevant information.
Gizmag is on the ground at Google I/O: stay tuned for more.