Play Portal 2 "cracked" in co-op!
NOTE! Edited/added part 2011-05-03 at the bottom!
This is tested and confirmed working with the SKIDROW release of Portal 2. It might very well work with other releases as well.
So, you want to be able to play the co-op part of Portal 2. There is a solution to make that work with your "cracked" game.
The solution to this one is really very easy actually.
Install the game as instructed. Apply cracks as mentioned or instructed. Edit your shortcut to the game. You must add -console
EXAMPLE: "D:\Games\Portal 2\portal2.exe" -console
Start the game with your new shortcut. If done properly you now have a console window where you can enter commands. Write down the ip-address of the computer that will act as host.
So, FIRST you want to start to connecting to the host. In your command window you type:
connect 127.0.0.1 (replace 127.0.0.1 with the IP of the computer that will act as server)
SECONDLY the server starts to host. This by loading any multiplayer map. In the command window the host types:
map mp_coop_start
When a map is complete the game will automatically load the next map. This with exception for a few times. We noticed that after every map where you are asked to "steal information" from a disc the game loaded mp_coop_lobby_2. The simple solution to this is just for the host to load the right map that should have followed, and for the other player to connect again. However, if you should turn off the game you always need to start to connect BEFORE the host starts a map.
(When ProblemVsSolution was playing we tried to play over the internet IP and over a Hamachi IP. Both worked.)
Here is the complete list, in the right order, of all the names of the multiplayer co-op maps in Portal 2:
mp_coop_start mp_coop_lobby_2 mp_coop_doors mp_coop_race_2 mp_coop_laser_2 mp_coop_rat_maze mp_coop_laser_crusher mp_coop_teambts mp_coop_fling_3 mp_coop_infinifling_train mp_coop_come_along mp_coop_fling_1 mp_coop_catapult_1 mp_coop_multifling_1 mp_coop_fling_crushers mp_coop_fan mp_coop_wall_intro mp_coop_wall_2 mp_coop_catapult_wall_intro mp_coop_wall_block mp_coop_catapult_2 mp_coop_turret_walls mp_coop_turret_ball mp_coop_wall_5 mp_coop_tbeam_redirect mp_coop_tbeam_drill mp_coop_tbeam_catch_grind_1 mp_coop_tbeam_laser_1 mp_coop_tbeam_polarity mp_coop_tbeam_polarity2 mp_coop_tbeam_polarity3 mp_coop_tbeam_maze mp_coop_tbeam_end mp_coop_paint_come_along mp_coop_paint_redirect mp_coop_paint_bridge mp_coop_paint_walljumps mp_coop_paint_speed_fling mp_coop_paint_red_racer mp_coop_paint_speed_catch mp_coop_paint_longjump_intro mp_coop_credits
EDIT: 2011-05-03
With update 3 from Skidrow there is now a file named COOP.cmd in your game directory. It will essentially do the same thing as this guide, but it does it for you. However, since you don't have Steam to track your achievements or progress you will still return to mp_coop_lobby_2 with no change on that course, making it loop the game-play to the first courses infinitely. So, the issue still is that you manually have to load the next level every time you get to that point.
If you want to use the COOP.cmd file to load the appropriate map you right click the file, choose edit and find the line almost at the bottom that ends with mp_coop_start. And then replace mp_coop_start with the map name you want to load.
In the COOP.cmd you will as host have the option between only lan games or not. Choosing only lan games will require your and your friends IP address to be similar to each-other, as if you are on a actual lan. If playing over internet I recommend not to limit it to lan and use your internet ip, that will work just as good, if not better, you then don't need to bother with Hamachi.
Choosing the option to not limit to lan games may also solve some of the connection issues ProblemVsSolution has gotten questions about.