any VLC Media users - enlarging view

at the top of the screen in the various menus, you should see
settings -
          these can be changed for both video & audio; just adjust the way
you prefer.

       As for slowing down, I guess you could
          (1) change the speed of the video
         or
         (2) insert some blank spaces - or duplicate images - within your
video.

       BTW - I'm assuming you're dealing with your own videos,
          because tampering with another's work would be considered
plagiarism.

       BTW 2 - I certainly hope someone else, with more knowledge, of this
will respond to you anon;
          the reason I keep my replies cc'd to the list.