Website Design – Does a video lightbox need a close button?

I'm building a portfolio website for their videos. When you click a thumb in a video gallery, a light box not exceeding 65% of the view window opens to display the video. You click on the dark part of the light box to close the video and return to the gallery. The light box does not page.

I'm almost done with the site and have started thinking about one of the UI design choices I've made.

At this point, it seems intuitive to click on the dark area of ​​the light box to close the video and return to the gallery. As it has become a very standardized behavior, but I know that I am biased.

My other argument to myself is that the video never completely covers the video gallery and that the dark part of the light box is only about 70% opacity. You would like to click on the videos to bring them back.

Do I need a close button? Am I taking too much risk for user frustration? I would love some opinions or even better, the theory, as to why or why I do not need it.