Those that love level creation will definitely enjoy these two
Operation Arrowhead trailers. Well, actually, calling them trailers is a bit disingenuous. They are more along the lines of video tutorials, and they cover the modding system of
Operation Arrowhead in quite some depth. The first tutorial, above, details the basics of mission creation: placement of objects, creating triggers, and linking events together. The second tutorial, below, goes into a little more detail with the scripting system. It's worth paying extra attention to the second trailer, as the developer does some tricks you might not notice if you just casually glance at it. While they aren't full of gameplay footage, they're intriguing regardless