At one point in the demo, Nilin is captured at knifepoint by a bounty hunter--apparently, someone knew she was alive and wanted her dead. This is where Remember Me's most novel mechanic, Memory Remixing, came in. These events are cinematic puzzles in which Nilin dives into someone's subconscious and alters a specific memory to her advantage.
Each memory starts off as a cutscene, displaying how things really went down. From there, you can rewind the cutscene in real time in search of "glitches," which indicate something can be altered. Changing the correct combination of events results in an entirely new memory--but if you alter too many things (or not enough), the Remix can fail, presenting tertiary situations that, while game ending, are still immensely fascinating to watch. In the case of the bounty hunter, performing a Memory Remix turned her from foe to friend, and Nilin escaped her clutches alive. The whole setup totally recalls Inception.