Disclaimer: This is intended for people who aren't entirely sure what a "game engine" is. I have more in-depth programming videos on my channel, this is just how I'd explain engines in general to a non-dev friend :) It's also one of my oldest videos from when I had very few subscribers, I'll redo it if I ever have a chance.

My Second Channel:    / thehappiercat2  
Subreddit:   / thehappiemakers  
Twitter:   / thehappiecat  
Facebook:   / thehappiecat  
Twitch: twitch.tv/happiecat