Memory Sequence 5:
You must complete the entire fifth memory in under 5 minutes! This is the first speedrun sequence in the game. It consists mostly of platforming sections. Only use slide assassinations and jump assassinations for killing enemies. The slide assassination is the quickest in the game and will save you a lot of time. At the start of the memory there's a little tutorial that explains slide- & jump assassinations. The time you spend in this tutorial does not count towards the total time! Cutscenes don't count either. You are even allowed to restart checkpoints when you make a mistake. Keep sprinting all the time and never let go of the sprint-button! During long climbing sections you can press X (PS4) / A (XB1) to climb even faster.
In this video I did it in 4 minutes, 17 seconds to earn the gold reward for beating the fastest time. There's plenty of room for mistakes when going for 5 minutes. You should aim for 4 minutes, 20 seconds if you want to work towards "The Completionist" trophy / achievement.