This is a tutorial on how to take files from portal, and merge them with the half life 2 files to gain access to the portal gun in half life 2, details in the file.


EDIT-
there was some confusion about this, allow me to clarify, this is NOT a replacement of anything, it should actually be named "half life 2 compaign in portal", this allows you to start portal, and begin playing in the half life 2 maps, going to certain areas of the map WILL load the next part of the game, so you could start from the beginning and play the campaign completely through with the portal gun as a default weapon accessed by going to the command console, typing "sv_cheats 1"then "impulse 101"
If you load the maps and receive a mass of errors, then you probably didn't extract thr "scenes" folder correctly. if that still didn't solve your problem, then your versiion of either game probably isnt legit.

this has nothing to do with garry's mod, nor will it work in garrys mod, half life 2 and portal are run on a different engine than garry's mod so it will not work.

any more questions contact me on steam, my username is in the file

heres a video of how to do this
http://www.youtube.com/watch?v=91KOaRbBrdo