The horde mode this time around comes in two different forms, one which has you using the set team of: Tracer, Torbjorn, Mercy and Reinhardt, and one in which players are free to choose any heroes.
Both modes have players dropped into an updated version of King's Row, tasking them with completing three objectives while fighting off hordes of AI controlled omnics. The mode makes for a great change of pace and I wish something like this would be added to the game permanently, especially since this event only lasts around two weeks.
Going back into the past means that we get to see younger versions of every character (all of which can be seen bellow). This event helps fill in some gaps, like the relationships between Overwatch members, their eventual falling out, and how the functioned during the peak of the omnic crisis. I hope to see more non-traditional events like this in future, especially if they help to build the narrative of the game itself.