Recently, Inti Creates shared a Christmas wallpaper and news that Azure Striker Gunvolt: Striker Pack includes a limited-time Christmas mode that is only playable on December 24-25, 2017.
The mode involves going through levels, which now have slippery ice floors and falling presents to obtain. The goal is to see how many presents players can pick up in a level, and levels feature Christmas-y music as well.
Inti Creates warned that the mode may not appear correctly if the date on the game console has not been set correctly.
Azure Striker Gunvolt: Striker Pack is available on Nintendo Switch.