Making gifs is crazy fun.
From the editor, load a level, bop around in it a bit, and then press CTRL+K (or CMD+K if you're on osx), then BE PATIENT, then BAM a shiny GIF along with a download link should appear in the console in a short few moments.
It's not the fastest generator in the world, and its speed depends on the length of the animation and the resolution of the game-screen in the editor.