Full list of all 51 Portal 2 achievements. It takes around 20-25 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there is 1 DLC pack containing 1 achievements.
Perform 2 aerial gestures before touching the ground in co-op
Never lose a cube in Chamber 6 of the Mass and Velocity co-op course
Win 3 co-op games of rock-paper-scissors in a row
Find the hidden companion cube in co-op test chamber
Complete all test chambers in all courses of co-op
Show that pit who's boss
Enter 4 different portals without touching the ground in co-op
Break 11 test chamber monitors
Refuse to solve the first test in Chapter 8
Find a hidden portrait
Catch a blue-painted box before it touches the ground
Examine all the vitrified test chamber doors
Discover the missing experiment
Complete all test chambers in the Excursion Funnels co-op course
Dance in front of a turret blocked by a hard light bridge in co-op
Stand in a defective turret detector
Save a turret from redemption
Complete Test Chamber 10 in 70 seconds
Break the rules in Test Chamber 07
Use an Aerial Faith Plate to launch a turret
Find the hidden signal in one of the Rat Man's dens
That just happened
This is that part
Master the Excursion Funnel
Do the same test twice
Place a cube on a button without touching the cube
Perform all 8 gestures of your own volition in co-op
Complete the first Conversion Gel test
Master the Propulsion Gel
Carry science forward
Master the Repulsion Gel
Press the button!
Make a break for it
Take GLaDOS' escape advice
Complete the first Hard Light Bridge test
Complete all test chambers in the Hard-Light Surfaces co-op course
Complete all test chambers in the Mass and Velocity co-op course
Complete all test chambers in the Team Building co-op course
Complete the first Thermal Discouragement Beam test
Reunite with GLaDOS
Celebrate your cooperative calibration success
Survive the manual override
Drop your co-op partner in goo while they are gesturing by removing the bridge under them
Place a portal under your co-op partner while they are gesturing
After completing co-op, complete Calibration Course online with a friend who hasn’t played before
Complete Chamber 3 in the Hard-Light Surfaces co-op course using only 5 total portal placements
Solve 3 co-op chambers in the Mass and Velocity course in under 60 seconds each
Complete Course 4 with neither you nor your co-op partner dying
Taunt GLaDOS in front of a camera in each of the five co-op courses
While playing co-op, hug 3 different people on your friends list
Never lose a cube in Chamber 6 of the Mobility Gels co-op course