The patch is in the Interlc folder, but the patches are messed up. follow the directions here to fix the patches: http://www.gog.com/en/forum/gabriel_knight_series/q_does_gabriel_knight_2_the_beast_within_feature_subtitles/perm=13/#p_b_13

Thanks. Does this also fix the audio glitches where you'll hear something that sounds like a disc scratching, or is that a whole other issue?

It should help.

So, where can I find the patch to turn interlace back on in GK2?

With the newest download I think it is built in, sticky from GOG here.

Hm, so there's no way to remove it or turn it off?

It's possible, look here: [url=]http://www.sierrahelp.com/Patches-Updates/GOGUpdates.html[/url]

For me, it looks better in fullscreen with interlace, but it's a question of taste.

For anyone who runs into this issue nowadays and came here through a google search:

Since gog is using a ScummVM based installation of GK2 these days going back to interlaced video is actually trivially simple. You only need to edit the gk2.ini file in the installation directory and change the enable_black_lined_video to true.