Full list of all 12 Portal: Still Alive achievements worth 200 gamerscore. It takes around 6-8 hours to unlock all of the achievements on Xbox 360.
Find all the Rat Man dens.
Once you have control of both portals, only enter the orange portal.
Complete the game without ever taking a bullet.
Beat all advanced chambers
Knock a turret over with a security camera.
Win a gold medal on a challenge map.
Trap yourself in a test chamber so that GLaDOS has to help you continue.
Beat 10 advanced chambers
Dissolve a turret.
Beat 5 advanced chambers
Cause a rocket sentry to destroy its own rocket when the rocket has been redirected back towards it.
Find the chicken's test results.