What is the difference between the director calling NG and CUT? Aren't they all remakes?

First of all, the director never shouts NG, only Cut. As the name suggests, Cut means stopping filming and the actors stopping performing.

The so-called NG refers to No Good. The shot is invalid. At this time, the director will tell the Script Supervisor that this item is invalid, and he will record that this item is NG in the scene notes.

As for those scenes where people are filming and laughing, they are not called NG, they are called blooper, make no mistake