I think the steamdeps file is out-of-date; I think recently they made it so that libjpg-turbo8:i386 is no longer a dependency (as per #658).
Then again, the last steamdeps.txt change I've seen was on December 21, 2012
oops, overlooked that, will be fixed in next update
Also jockey-common is reported as dependency in steamdeps.txt but not in the control file of the package deb. Notice that jockey doesn't exist in Debian, so this might cause problems to Debian users.
Nothing extracted yet.
On a fresh installation of steam_latest.deb with version information 1.0.0.22, the control file does not list libjpeg-turbo8:i386 as a dependency. However, once the bootstrapper package is installed and the additional files downloaded, the sudo prompt informs the user that the package must be installed.