This movie generates the save files required to play back the New Game+ Neutral V2 movie file correctly.
UNCHECK
Runtime > Prevent writing to disk before playing this file back to ensure it generates the files correctly.
Make sure
Movie > Auto-restart game is on.
Make sure
Runtime > Time tracking > clock_gettime() monotonic is checked, otherwise the game won't progress past the intro/first couple frames.
Save files can be found at
/home/YOUR_USERNAME/.config/UNDERTALE_linux_steamver. Make sure to delete existing save files before playing this movie.