Alice fell down the rabbit hole in 1865. Tron was scanned into the grid in 1982. So becoming part of the story is not a new idea, but it's still delightful when done well.
A young adult series called "80AD" propels two kids into their computer game. Each volume presents their adventures on a separate game level, with each level focused on a different world culture and its history and mythology in that year. I've not read these yet, but at first glance they seem of better quality than most Smashwords freebies.
These are all FREE and DRM-free! So you may level up on any reading platform you choose!
80AD - The Jewel of Asgard (Book 1) by Aiki Flinthart
https://store.kobobooks.com/en-US/eb...-asgard-book-1
80AD - The Hammer of Thor (Book 2) by Aiki Flinthart
https://store.kobobooks.com/en-US/eb...of-thor-book-2
80AD - The Tekhen of Anuket (Book 3) by Aiki Flinthart
https://store.kobobooks.com/en-US/eb...-anuket-book-3
80AD - The Sudarshana (Book 4) by Aiki Flinthart
https://store.kobobooks.com/en-US/eb...arshana-book-4
80AD - The Yu Dragon (Book 5 -The Final Adventure) by Aiki Flinthart
https://store.kobobooks.com/en-US/eb...inal-adventure