Just to clarify, do you play it on pc or phone? Also, you did unpack all the game from the rar archive, right?
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I play on PC and yes, I fully unpack all the files, and place it in it's own folder in my Games Folder.
Edit, as of 17/07/2023: Huh now it's working??? I has to restart my laptop for some updates, and then, on a whim, I opened up the game, and used the save file that was close to ending one, and the video played fine then. Maybe it was a problem on my part. In that case, I'm sorry for the trouble, and I greatly appreciate you translating this game~