Mirror Worlds is a game mode introduced in Angry Birds Space on January 21, 2015, alongside Brass Hogs. In this mode, the levels are flipped, made considerably harder and the colours are dulled (though this can be turned off in the game's settings). Mirror Worlds levels are unlocked by three-starring normal Space levels. The villain Hektor Porko makes his debut here. He can only be seen in Mirror Worlds versions of levels.
Continuing off of Brass Hogs, the birds find a vortex on one of the planets. The birds, curious, venture into the vortex and end up in a flipped dimension and are questioning the world they are in.