Jerkass: Tom mentions that Dana thinks he is this. Dana confirms it.
Painting the Medium: By making the cameraman a character in this Show Within a Show. There's a scene showing Dana and Tom saying some very private things about Zack, and eventually revealing that Zack was there filming the whole thing. A later scene lampshades the fact that we the audience cannot see what Zack cannot film. Don't ask how he can jump between cuts mid-sentence in unedited footage or remain unseen while filming Tom at face level in that closet.
Pants-Free: Tom records the vlog wearing his Batman boxers and spends the whole episode like this, including when they are outside.
Record Needle Scratch: Played as Dana says "That's it?" in response to Tom's self-pity story about his brother being generally superior to him throughout his childhood.
Sarcasm Mode: "Aww, how tragic. Watch as my hatred turns to pity."
Knife Nut: One of the interviewees plays with a folding knife throughout his scenes, then lampshades the trope:
Interviewee: Are you afraid of the knife?
Psycho Ex-Girlfriend: Tom's Ex Shannon pops up, pissed off because Tom didn't tell her about the casting for a female actress and she had to find out about it on Facebook. She also seems to think they're still together.
Terrible Interviewees Montage: The actual montage included Zack's uncle (who's just as strange as he is), a porn-star, a girl who may have come for the counseling session the team hijacked, and possibly a serial-killer.
Hidden Depths: Zack's knowledge of After Effects and his degree in art, which may or may not be real.
Hypocritical Humor: Tom tells Dana that anyone who always assumes a person can't do something right will eventually be proven wrong...right before Tom immediately scolds Zack for talking, as if assuming he can't possibly contribute.
Insistent Terminology: Dana and Tom are trying to discuss their characters separately from themselves, in order to keep themselves distant from their roles. It leads to a lot of "I will... I mean she will..."
Visible Boom Mic: In the scene in the kitchen as Tom describes how crazy Shannon is, you can see Zack's brother Dave holding the boom mic and Zack off and on throughout the scene. Their reflection in the window is right in the middle of most of the shots to boot.
Fourth Date Marriage: Tom believes this will happen with him and Porn Girl. He's dead wrong. Not only is she ticked off about Zack following them around, she's also very annoyed that Tom hasn't tried to sleep with her yet.
Drama Bomb: Although there's some humor, this episode is more serious than usual.
Fantasy-Forbidding Father: Mark thinks that there's no such thing as a PhD in art, and he's disappointed that Zack got one instead of "fulfilling his potential" by focusing on his cinematography career.
Wham Episode: Where do we start? Zack quits Echo Chamber and moves in with Gaelyn. Gaelyn kisses Zack, and Zack apparently returns her feelings. Mr. Administrator is an admin for The Other Wiki. It's vital to Mr. Administrator's plan (which doesn't get revealed until the next episode) for Zack to return to Echo Chamber.  is cancelled.
Who Are You?: Zack's dad gives an anguished one to Mr. Administrator in the last seconds of the episode.
Even Evil Has Standards: One of the instantiations is called "weirdo" for the rest because of his exaggerated like of the word "gurt".
Facial Markings: One of the ways to distinguishMr. Administrator's instantiations. Naturally they are at the temples, which are above where Mr. Administrators face is normally seen by the other characters.
Man Behind the Man: Apparently, Administrator Prime is behind Mr. Administrator, the latter also being a copy of the former. Plus, there are lots of other copies of Administrator Prime and he's behind all of them.
Recursive Reality: Administrator Prime explains that there are infinite story layers, possibly implying that the viewer's reality may be one such layer. In other words, it's turtles all the way down.
Retcon/Snap Back/Status Quo Is God: Forcing this on Zack is Mr. Administrator's plan for getting Echo Chamber back "on track", whatever that means. Unfortuantely, that requires a lot more work than a simple Handwave.
Episode 4: Dumbass Has a Point, in which the gang is working on trying to come up with a better graphic effects opening montage. Tom is frustrated and is baffled as to how to make the montage work, until Zack—of all people—comes up with a surprisingly insightful suggestion.
Episode 5: Unresolved Sexual Tension, in which Dana and Tom try to determine whether there should be any between their characters on the show. Things get complicated when he reveals he's attracted to Dana. And Zack will always be alone.
Episode 6: Psycho Ex-Girlfriend, in which Shannon reappears and is just generally creepy. Also, Dana snarks a lot.
Episode 9: My Beloved Smother: Zack takes Gaelyn to meet his tyrannical father. Drama ensues.
Episode 10: Broken Ace: Tom challenges Dana to find out if  really needs her.
Episode 11: Coming-of-Age Story: Zack makes choices that will determine his future—and the future of Echo Chamber.
Episode 12, The Season's Finale: Mind Screw: When Mr. Administrator is forced to deal with the fallout of Zack's decision, the secrets of his identity, his motives, and the nature of Echo Chamber itself are revealed.
Cerebus Syndrome: Slides into this gradually; the first somewhat serious arc begins in episode 3, but the arc episodes get somewhat more common and serious in season 2. The last four episodes of season 2 each advance at least one of the show's arcs, all of them are Darker and Edgier than any of the episodes that came before them, and the season 2 finale in particular implies that there will be much more of this syndrome in the third season, (which Word of God says will be the last one).
The Danza: Almost all the characters are named after their actors. The only exception so far is Umphrey Bridgeport from Tyrant Takes the Helm, who is played by Stefan Dezil. However, given The Reveal at the end of that episode, it's probable that this isn't the character's real name.
Lampshaded in episode 10; the only defining features of Zack's sock puppet are a derpy tongue poking out and a camera.
The Season 1 finale has Zack talking with his face partially obscured by his camera and then when he pulls it down he is facing opposite the camera.
Zack starts to avert this slightly more as of Season 2, in several episodes (notably 2x09), there are moments where you can see pretty much all of him except his eyes.
The Administrator, who is both out of frame from just below the eyes and up, and back-lit so that his features are almost completely obscured by shadow. That's all we're saying about him. He scares us.
In 2.11, Zack is finally fully visible. And in The Stinger, so is Mr. Administrator.
Only Sane Employee: Dana. Justified twice - Tom recruits her specifically to fill this role, and she mentions in episode 3 that being one makes her feel much more useful than any of her other jobs did.
Type 1. In the first episode Dana suggests they have a Show Within a Show in their first vlog in order to demonstrate the trope, which from the viewer's perspective would make it a Show Within A Show Within A Show, but Tom decides against it. In the other episodes, we see them making the vlog, but we never see the finished vlog itself.
Season 2 has , a competing vlog from The Other Wiki.  itself has a Show Within A Show, as the excerpt played is explaining that trope by doing a Show Within A Show of its own.  also talks about Echo Chamber in a different episode.