"I did some puzzles, did some combat encounters, just to show it had some design legs. Then we just played it and had a blast with it. People saw the potential.” 

- Senior designer Jake Keating disclosed the origins of Titanfall 2's Effect and Cause mission in an interview with Waypoint.

As a warning, if you haven't yet reached the Effect and Cause mission in Titanfall 2’s campaign nearly everything mentioned in both the original interview and this article could be considered a spoiler. 

The mission Effect and Cause features a mechanic that Respawn senior designer Jake Keating had wanted to explore long before the Titanfall series even existed. That single mission gave players the ability to jump between two timelines instantaneously while exploring an abandoned science facility.

Keating revealed that when players jump through time, they’re actually being teleported between two versions of the level, one floating directly above the other. To accomplish this, the team had to devote more time to Effect and Cause than any other level in the game.

In the full interview with Waypoint, Keating explores more of how Respawn created the mechanic and how different elements of the level were precisely tuned to make time travel feel fluid.