Though the open-world crafting phenomenon doesn't really have an end, any more than a big box of assorted LEGOs has some final way to assemble it, Minecraft does have an endgame. The original PC release was expanded with a “final” level and boss in 2012, but the Microsoft-branded Windows 10 version and the Pocket Edition on Android haven't had access to it so far. According to Mojang's developer blog, The End is nigh, and it has a gameplay trailer.
In the appropriately-titled “Ender Update,” which also finally brings the game up to version 1.0, players will be able to travel to a Lovecraft-inspired alternate dimension complete with new creatures and new crafting materials. There's also the final boss, the Ender Dragon, and slaying it will grant players a peek at the elusive credits and a feel-good achievement. It's best to tackle this final challenge in a group, if you can.
Other features promised in the 1.0 update include the World Seed Library, polar bears and cubs in appropriate environments, and free access to the Minecraft soundtrack (though that will be offered as a separate download). Exactly when Pocket Edition will receive this update hasn't been shared yet, but Mojang usually posts these announcements a few weeks before they go live. Hopefully you'll be able to get a little dragon-slaying done before the end of the year.