Funny Background Event: In older episodes, sometimes Megan's sister would walk in and suddenly leave, or you can hear her mother telling her to keep it down. Justified, as she still lived with her parents at the time.
Still happens from time to time, especially if she has someone else in the room.
Every now and then, one of her cats comes in. In Episode 197, the two of them are sleeping on her bed, and sometimes react to her screaming. They then suddenly get up at once, and leave half-way through when she reaches the, er, climax.
Gilligan Cut: In Episode 129, this effect forces the FanFic Critic into reviewing the infamous Cupcakes.
I Need a Freaking Drink: Has been becoming more prominent the worse the story is, especially if the fanfic involves homicidal ponies.
Episode 184 had her drinking by the, err, "climax" of the story.
Laser-Guided Amnesia: Susan, after being killed and then brought back to life by the FanFic Critic, went nuts. The FanFic Critic, feeling guilty for her role in Susan's insanity, made sure her memories of the incident were erased. Susan got them back eventually in a much later season.
Reason You Suck Speech: She has her rants, most notably if the fanfic has atrocious grammar and/or awful content.
Susan of all people got chewed out in Episode 192.
Running Gag: Susan preventing the FanFic Critic from killing herself.
The FanFic Critic trying to find a third thing to say at the end of her videos.
Screw This, I'm Outta Here: The Critic tried reviewing the first issue of the infamous Sonichu webcomic, but she finally became so disgusted that she quit three-quarters of the way in it.
Happened again in Episode 189 with a My Immortal-esque Justin Bieber story. She only got through an eighth or less of the story.
Once more in Episode 194.
The cats in Episode 197.
Talking To Herself: Currently, Megan plays three characters: the titular character, Susan, and Lesbian Jesus (who was created by another fanfic reviewer on YouTube named Aliento). She did play another character called "the Crappy Arthor" back in her first few seasons but that character was written off.
Throw It In: The entirety of Episode 106 was done impromptu and in one take, because it angered her so much. In fact, most of her show is impromptu with the exception of a few episodes.