BioShock: Infinite Crosses Alternate Realities. No, Really!

The player's large-chested sidekick Elizabeth has a unique ability to manipulate the tears, calling forth various choice mechanics that affect gameplay in various ways. 

In an example scenario, Levine shares that players could theoretically choose between having Elizabeth pull either a turret, skyline rail, or a group of friendly NPCs into the world, each of which would present different options to the player to deal with the current situation. 

Make sure you watch the video all the way through, as the visuals depicting Elizabeth's reality-distorting powers are impressive to say the least.