Gate:Rebirth

This is a story of what happened to a certain Okabe in the Beta Attractor Field. It offers an interesting look at Attractor Field Beta and introduces a couple of new characters, one of which is Kurisu's senior lab partner.

What do you get when you cross a microwave with a cell phone? Apparently, a time machine! Self-proclaimed mad scientist Okarin and the Future Gadgets team now have the ability to send text messages into the past. Will this newfound power be used for personal gain? To change the world? Or for something much more sinister... ? (Source: Udon Entertainment)

The Distant Valhalla is a side story set in the Alpha Attractor Field. It is set 1 year and a half after the Rounder Raid on the lab, and is about "Operation Valhalla", Okabe's plan to escape from SERN's captivity.