I recently downloaded ES2 through Steam-Proton. The audio and video are flawless, but all the cutscenes are missing. The videos play fine in 'Local files' folder, and everything is thumbs-up in the game settings page. Any suggestions?

That's likely a codec issue but given its on Proton...... its a bit of a unknown how you'd fix it. Probably should ask on Wine forums about trying to install video codecs 

WIll do, thanks for the tip

I've had this problem in the past, fixed it, and have it again. I don't use Proton, however. I think it was something in Settings before -- something weird you wouldn't expect to affect it. I really don't remember what it was, though. I may play around when I get off work. Good luck in the mean time, though.