Avatar Awards:Unlock the following Avatar Awards by performing the corresponding tasks:AWARD – HOW TO UNLOCKCompanion Cube – Complete Portal 2 Single Player.Love Shirt – Hug 3 friends in Portal 2 Coop.Portal 2 Hat – Survive the manual override.Portal 2 Shirt – Complete Portal 2 CoopTurret Shirt – Complete Test Chamber 10 in under 70 seconds.Alternate Title Screen:Complete the game to unlock an alternate title screen.Singing turrets:Find the turret inside a ventilation grate just past the elevator in Test Chamber 16 and jump over it to get the Refraction Cube. Then, use the laser to destroy that turret to open the grate. Enter to find four turrets singing a song.”Door Prize” achievement hint:When going for the “Ship Overboard” achievement, there are three metal doors in the hallway once you enter the door behind the filing cabinet . If you activate the doors, Cave Johnson talks about the tests. Activate all three doors and the achievement is yours.”Final Transmission” achievement hint:On Chapter 2 “Test Chamber 6″, get the radio that appears in a clump of garbage into a window above the chamber after you hit a button. Make your way back through the level and place a portal on the pad across from the window, then use the launchers to get through the portal and into the room past the window, with radio in hand. Take the radio up to the wall and the achievement is yours.”No Hard Feelings” achievement hint:On Chapter 5 “The Escape”, reach the conveyor belts carrying droids to the incinerator. Use a portal to get onto the conveyor belt and walk on the belt until a droid with a working laser beam appears. Pick it up and the achievement is yours.”Pit Boss” achievement hint:On Chapter 9, after Wheatley