Nightmare Fuel: The nightmare battle itself; A creepy silhouette with demonic eyes that is constantly trying to kill you is bad enough, but the background is also fairly disturbing, with words like "anathema" and "demon" floating around constantly. And that's not even counting the music...
Alternate Character Interpretation: At first glance, Maldark seems like a typical Big Bad, but one could also make the case that he's simply applying the programming that Max wrote for him to the real world.
Ensemble Dark Horse: Compare the reception this show got compared to the other live actions on Cartoon Network (aside from Tower Prep) and you'll get the gist that some liked it compared to those shows.
Out of Order: The episodes were shown out of order. The production code for the first premiered episode (not including the movie) shows it was made 6th. They try to stop some confusion with a recap opening but suddenly the Clan now have an HQ and it's treated as normal.
Fridge Brilliance: The four angels are actually the ghosts of broken promises made by Dennis' father to his deceased family members that he would become a doctor. In Chinese, 4 (四, sì) is considered an unlucky number because it's pronounced nearly the same as the word for "death" (死, sǐ).
Fridge Horror: Dennis' father and paternal grandfather both died of liver cancer, while his paternal grandmother and great-uncle are implied to have died of the disease as well. It is possible that Dennis himself may be at greater risk for liver cancer as he grows older, as well as any children he may decide to have in the future.
Genius Bonus: Of the four angels, the red-haired angel is the most aggressive, using their Game Face on Dr. Rodriguez to get her to re-enroll Dennis, refusing to let Dennis change his mind about studying gastroenterology, and grounding him when he tries to quit. In the original Pac-Man game, Blinky the red ghost is the most aggressive enemy and always directly targets Pac-Man while in chase mode.
Hilarious in Hindsight: At university, Dennis starts seeing his father's face on every statue he passes by. This was long before the "Everywhere I go, I see his face" meme from Spider-Man: Far From Home.
Fridge Brilliance: A meta-application of this. The storylines of Mariocraft, The Goomba Revolution, and Mario vs. Bowser's Mega Submarine all got practically forgotten, with TGR having only one mainline story video. The Hostile Show Takeover by Level DOWN is a brilliant way for Level UP to incentivize himself to stick to the storyline of God Mode Luigi Takeover all the way through. It gives an In-Universe reason for Level UP not to focus on any other storyline.
In "When Everything Mario Jumps On E X P A N D S", Bowser is shown to give up immediately after the first life spent against him. Paying attention when Mario abuses his ability shows that Bowser is the only one to have 3 lives in those who lost one, whereas everyone else (aside from Luigi, who had 99, and Waluigi, who lost his last one) had 2 lives left when the world was crushed by a giant coin. And in the big encounter, Mario causing the bridge to grow costed Bowser his second life. Of course he'd not want to take any chances when one more mistake would cost his life.
Tear Jerker: In Mariocraft 4, the Magikoopa shows Bowser buried under dirt, as apparent proof that Mario died out in the open. Bowser is genuinely upset and horrified to see his greatest nemesis seemingly gone, and NOT at his hand. Granted, we find out shortly after that Mario did survive the ambush and even saves Wolfie from the attacking Skeletons, but neither Bowser nor Wendy know this, who both mourn for Mario.
