If you want to do that- click Other Settings on the main menu

Then click the file button here to add your video(.mp4) file

Right now it only supports .mp4 video files- I'll expand that to other formats in the next update-
If you want to go back to using the default NP pre-scene countdown click the red X to the right of the file button-
I also added the mosh pit from the Thrasher scene to the level editor objects so you can drop mosh pits where ever you'd like.
Changed files in this update