Before we call it a problem with cutscenes, I'm first going to look for answers in the level itself.
I downloaded Vengeance by Bass from knyttlevels. It was a 47.2MB knytt.bin file. Is this the same one you downloaded?
Playing it, no intro cutscene plays for me.
Looking into the folder...
there is no Intro cutscene folder! Which settles that.
There is a cutscene called Ending, but
it's just the default "You win!" screen.
The game does not have a custom-named endings set in any rooms. I searched World.ini and found no such thing. This means that
the Ending cutscene should play when the player beats the level. But that's assuming there is a WIN object at the end of the level; I don't want to spoil the level by looking through it in the editor, but I'm assuming this is a finished level with a WIN object at the end.
The other cutscenes are set and do work for me.
Like if you walk left from the beginning, one happens quite early.
It is notable that none of the cutscenes have any music. But this doesn't appear to be a problem, per say; the author just didn't get to giving them music (or he wanted them to be silent). Their lines in World.ini under [Cutscene Music] is blank.
So if none of them are playing (such as the one very early on where
, then you may have a unique problem on your hands.