I have made two projects to do with portal: the Ferpetual Testing Initiative and Want You Gone. The links are below and hopefully the names are self-explanatory.

FTI: http://scratch.mit.edu/projects/11916450/
WYG: http://scratch.mit.edu/projects/12155250/

I'm a big Portal fan, so kudos on the subject matter!

The FTI project seems stuck for me. I notice WYG is a work in progress, so I'll wait to see the finished version.

I like the actual sound effects of the turret in FTI. Did you pull those directly from the game file? If not, did you know that you can access the sound banks for Half-Life engine games, including Portal? Requires a little know-how and a program called GCFScape. Google is your friend. Happy programming!

I got the sounds from a file sharing site and if you were wondering, I did use HL2 sound effects in the Scratch Land trailer.