Right now, there are tracks for Reefer Madness, Night of the Living Dead, Plan 9 From Outer Space, Road House, and The Fifth Element, with Star Trek V coming soon.
Last night we watched The Fifth Element; it's the only one I've tried so far. Here's my judgement: A good idea, but the execution needs work. Also, you probably shouldn't listen to a riff for a movie that you love unironically. I love The Fifth Element and not in a cheesey way. So, this seemed more like I was watching the movie with an obnoxious friend who was sometimes funny.
It was just Mike, along with this "DisembAudio" voice from time to time. For Star Trek V, he'll be joined by Kevin Murphy, which I think will probably be better than just Mike alone. Also, I'm not emotionally invested in that film, so I'll be more open to having it made fun of.
I think the Boy enjoyed it a lot more than I did. But also, I am sick, so that may be colouring my enjoyment of pretty much everything right now.
So, in conclusion, I didn't enjoy this particular riff very much, but I think the idea has a lot of potential.