More than 5 years ago I read a story about this.
Set in 2020 Italy. One school boy's hobby is creating and playing Net-Plugged Games, which apparently have great graphical detail and can be created on a whim. He is creating his latest one to then play it and has the feeling something is lacking, when his little sister comes and changes one of the eyes of the character, giving the (female) character a blue and an amber eye. The boy, excited, starts the game.
Turns out the game creates the story about that girl being a bit magical, and absorbing energy from the sunset by covering her blue eye and looking at it with the amber one.
Things happen, and it turns out the setting of the game is in year 0 Christmas. The boy spots roman soldiers, Mary and Joseph, but decides to not let his character know.
In the real world, the boy finds a big moving nativity scene (some hobbyists do that) created by a Catholic priest in his town's church. They make friends. More things happen, and both the nativity scene and the game stop moving. The priest says something about an apocryphal gospel stating time stops, and that both 'toys' (the nativity scene and the Net-Plugged Game) stopped because they are well-made. The boy then finds out the magical character girl has been moving when the time is stopped, and that's her magic power.
At some point, the boy plays as a priest inside the game, remarking how novel the way of controlling him is: he has to chant prayers in latin into a microphone to make the priest "fight".
As you see, I remember quite a bit of details about the story, but I do not know its name nor its author. Please help?