Portal 2
51 Achievements
20-25h
Professor Portal
After completing co-op, complete Calibration Course online with a friend who hasn’t played before
1.6%
How to unlock the Professor Portal achievement in Portal 2 - Definitive Guide
MailOrderCowb0y
TrueAchievements
TrueAchievements
-One player must have beaten the entire Co-op before and one player must have never done the tutorial.
-The player who has never done the tutorial must never been in a chamber, the central hub is fine.
-Single player does not affect this, so you can have played the whole single player and it won't affect this.
-If you are going for other achievements, such as Friends list with benefits or other similiar co-op ones, skip the tutorial by pausing during the opening cutscene and returning to the hub.
-This cannot be done split-screen, must be two players with Active X-box Live accounts
-The only required chamber is the tutorial chamber where you acquire the gun and calibrate weight variances, which can really upset humans if you bring up :)
Hope this helps.
B. This has to be with a friend who either:
I: invited you
II: you invited
this can't be done by jumping into a random game and sending a friend request to the first person you find who hasn't started Co-Op, you gotta drop and reinvite. My brother found that out the hard way.
dropK1CK ninJA
TrueAchievements
TrueAchievements
You cannot get this achievement on split screen.
You have to have them on your friends list.
You can also create temporary accounts that get 1 month of free Xbox Live Gold and you can get this achievement with a friend.
They need to generate a new Windows Live ID -- http://bit.ly/mRbajB -- (I went with a generic, DKBOT e-mail address). Sign in with a new account on your Xbox. Attempt to sign-up for Xbox Live Gold, select the "Upgrade Later" option and sign-up under a Silver account. The next screen will offer you a free month of Xbox Live Gold with your new account and accept this offer.
There you go, a free second account and you don't have to find a 48-hour code or attempt to track down a new friend who hasn't started the co-op.
+1 from Me.
Crimson Crunch
TrueAchievements
TrueAchievements
1.Complete coop with someone.
2.You and your coop partner create a new xbox live account each / use a 48 hour trial on 2 seperate accounts.
3.You play the tutorial with the other persons 2nd account.
4.They switch back to normal account and you switch to second account.
5.You then do the tutorial again, opposite of 3.
6. You both should have the achievment with normal accounts which did 1.
Make sure that you are Friends with the other accounts when you do the tutorial with them,Or you will not get the achievment.
Dark Karbon
TrueAchievements
TrueAchievements
Step 1: Search for a random player.
Step 2: Look at the players achievements before the game starts.
Step 3: Quit out of the match and send a friend request if they have no co-op achievements.
Step 4: Invite them to your game and complete the Calibration Course.
The other player MUST be on your friends list BEFORE the game starts.
Quacky 2 Ducks
TrueAchievements
TrueAchievements
Tranierx
TrueAchievements
TrueAchievements
You will need either two discs or one digital version for this method.
Note: To access the 360's home button (
) functionality on your Xbox One press 
+
.- Make sure that you have completed co-op with your main account first.
- Make sure one of the Xbox Ones is the gold's home Xbox (Settings > Personalization > My home Xbox). I will refer to this as the Gold Xbox One.
- Log into the Gold Xbox One with your 2nd account and launch the game. Send your main friend request from the 360 dashboard (+).
- Launch the game on your second console with your main account and accept the friend request.
- Start co-op mode and invite your friend.
- Complete calibration course and unlock the achievement.
Jarie Suisen
TrueSteamAchievements
TrueSteamAchievements
---Requirements and unlocking---
1) You must have already completely finished Co-op Mode.
2) You must complete the Calibration Course (the very beginning of Co-op Mode) with someone who is already on your Steam Friend List who has not played the Co-op Mode at all. (As in, if they have entered Co-op Mode at all... it is impossible to get this achievement with them. Technically, they can have safely entered the hub, but if they have it's very likely they did more and are ineligible.)
If you have met the requirements, you will automatically enter the Calibration Course when you start Co-op Mode with your friend and then unlock the achievement.
---Help section---
Due to the stupid ease that this achievement can become practically impossible to get (by not being able to find some person to friend that HASN'T broken the second requirement because... why would they have the game and NOT have played it, right?), here is a trick that thankfully works for Steam players. (Not sure if this can work for Xbox at all, since, as far as I know, any second account will have to purchase both the game and Xbox Live... and then make sure you don't mess up. I never have been able to get this on my Xbox account and don't know anyone that I can get it with. Ugh.)
Requirements:
1) You must have finished Co-op Mode already (obviously)
2) Have a friend that also has Portal 2 in their own Steam library. (Since a game can not be accessed from a shared library by two players at the same time)
3) Your friend makes a dummy account (which will have access to the game via Steam Family Library).
4) FRIEND THE DUMMY ACCOUNT (If they aren't in your Steam Friend List before you start the game, it will not count and you'll have to use another dummy account.)
5) You invite the now-friended dummy account to join your Co-op Mode so they can supply the "new player" position in the achievement.
6) You then can do the same for your friend (assuming they haven't already unlocked the achievement.)
-Credit: Thanks to the guide made by user "rapphaelfs" on the Steam Community (https://steamcommunity.com/sharedfiles/filedetails/?id=33395...)
technole, and, Spikey654
UNOBTAINABLE DUE TO SERVER CLOSURE
This trophy can only be obtained online, and can be unlocked using PSN and/or Steam friends.
After finishing all co-op chamber courses, you will need to play with a "new" PSN or Steam friend whom has never played co-op before and complete the Calibration Course tutorial with them for this trophy. If you can't find a "new" player, then you and your Co-Op partner could each make/use a new PSN account that has never played Co-Op and trade off that way to give each other the trophy.
It is confirmed that you cannot backup and delete your save file to be eligible for the trophy. As you are required to link your PSN ID to Steam, by removing your save the game will re-download your recent save from Steam Cloud. So if you try to join a friend, it will take you back to the hub rather than the Calibration Course tutorial.
You will know you are eligible for this if you get the introduction cutscene before the Calibration Course once your friend joins the invite. For more information on Steam, how to earn this trophy using friends on Steam, or how you can potentially earn this trophy by yourself using your Steam code, please refer to our PS3 & Steam Integration FAQ.
If you need to locate a Co-Op partner, please refer to the Co-Op buddy thread.
For more information about linking a Steam account to your PSN account, and frequently asked questions about PSN + Steam integration please refer to our PS3 + Steam Integration FAQ
BoogerMen
stratege.ru
stratege.ru
If you cannot find such a player, then as a way out, you can register with your partner using a new GamerTag, add the newly created Tags to the friend list and pass. (GOLD 48 hours can be purchased on plati.ru - it’s not expensive).