Nintendo had scheduled a lengthy 24-hour maintenance window to tinker with the Nintendo eShop today, but have finished whatever they wanted to work on behind the scenes earlier than predicted.
Access to their digital store has now been restored, having originally been planned to be out of action until 3am GMT (4am CET) on Tuesday 3rd November. There are no immediately noticeable changes, the layout remaining the same in Europe and no related announcement having been made on Miiverse aside from apologising for the inconvenience.
Whether there is any incoming surprise, or if Nintendo had simply taken the opportunity to upgrade their servers is unclear. But, happy shopping once again!
Thanks to everyone for your patience. Our maintenance is complete, and you can now access the Nintendo eShop.
— Nintendo of America (@NintendoAmerica) November 2, 2015