Perform a perfect landing with the speeder

Get a high score in an arcade game

Collect all trophies

Use bricks or bottles to lure an infected into attacking a human

Defeat Black Fang without getting hit

Pick up the metal detector

Engage in all optional conversations

Win the brick throwing contest

Collect all comics

Break into every locked door using shivs

Find all training manuals

Upgrade and then break one of every melee weapon

Leave Ellie hanging after a job well done