The following command:
download_depot 337350 337353 6888663543024499238
yields a "Manifest not found" error, so it appears to still be broken. However,
Depot Downloader (linking to my post) can be used to get the correct version. The command would be the following:
./depotdownloader -app 337350 -depot 337353 -manifest 6888663543024499238 -username <Steam_username>
from within the directory Depot Downloader is located. "sudo chmod -R 777 *" will have to be run afterwards in order to be able to run the game (at least I had to).
For the record, there's a setting in the game that allows it to run in windowed mode.
EDIT: So....I can't get it to sync at all. clock_gettime() gets set again if I run the movie file, even if I uncheck it. Running with it unchecked causes it to not run at all. Doesn't matter if the game's on windowed or fullscreen. It desyncs around the third stage. I'm running libTAS with the "~/.steam/bin/steam-runtime/run.sh libTAS" command, as a note.