Well, most of the 'lingo' isn't real lingo. I'm pretty sure they made up almost all of them. Glob, Mathmatical, etc, whatever. Princess Bubblegum has caused...uh, well directly like three issues? The random humor is there, but at most, it only makes up about 1/3rd, and I can't even remember gross-out humor. The Lich was only in 'trapped' in one episode in sap, though most of the series he's trapped in some form, or doing something.
Fuck. Supporting character episode's take overs.
Finn's character development is also there. He cares a bit more about his actions, is more willing to do things alone, and seems less enthusiastic.
I mean, if the video only took like, the first two seasons, and described THAT, then it'd generally be a pretty good explanation, but as with most people who did this, he probably watched the first season or two, read a couple of blurbs, and read a summary on tvtropes or soemthing.