Thinking with Time Machine

Thinking with Time Machine is a Portal 2 modification featuring a new gameplay element known as the "Time Machine" which allows the player to record and play back their actions in the game world.

Plot
After completing a tutorial, you run across an unsolvable test, until you press a button and a record player falls out, followed by a Borealis hologram, which cracks a hole in the wall. You discover the two co-op Bots, saying that they shut down GLaDOS. They say they will keep tabs on Chell, and the new "Time Machine" device. GLaDOS tells you to go back in time, and the chamber opens.

You are then tasked with completing 9 highly challenging test chambers.

Mechanics

 * "Time Machine" device
 * Accurately recreates the player's actions. Activated by hitting the R (default) key, then the Q key to stop. The F key activates the mechanic and enable the Machine to start replicating the actions.