A Space for the Unbound

On the second "real world" day, at one point of the story you have to go to the local arcade where you find the Future Fighter machine.
The aim is to get at least 1500 score, beating one opponent gets you 100 points so you need to beat 15 of them.
The fighting is pretty easy to understand (and it's literally the same as what you have to do in the story at that point) you'll need to match the button prompts in a given time to hit and push the button at the correct moment to defend.
The game gets slowly harder and harder with each new opponent, at around 13-14 you have to really concentrate not to mess up the buttons.
It may help that you can pause the game the moment it shows the sequence and although the settings will partly overlap it, you can still see the sequence and train a bit before unpausing the game. And again, you don't have to beat the 16th guy, the assassin, it's enough if your score matches with the top one.