Why does Sofia hate TASCorp so much, even for an MD-5 member? Well, considering that TASCorp are involved with her sister's death...
In the special Season 1 soundtrack video, we see Tari casually playing video games in her room, which is full of stuff. In particular, there's a stack of books. The ones whose titles we see seem to match her interests (ducks and cybernetic technology) except for one book titled "the Hidden Meaning of Dreams". However, this makes sense when you consider that Tari is still an amnesiac who has no idea who she was before she woke up in that lab. This book implies that she's trying to find hints to her past life through the unconscious messages in her dreams.
In the mainline Meta Runner series, Theo is a hyperactive go-getter who's a little too familiar with the experience of death. Theo in his spin-off series, however, is extremely lazy and unmotivated. Why? Because, as is revealed at the end of the Ultra Jump Mania pilot, that Theo is from MD-5's UJM cartridge, which was likely sitting on a shelf, untouched for who knows how long. This explains why that Theo is used to just not doing anything. The Theo in the main Meta Runner series comes from TASCorp's game cartridge, which was used to speedrun the game repeatedly. This explains Theo's boundless energy and pride. There is also a LOT of trial and error when it comes to professional speedrunning (briefly seen in a flashback in season 1 episode 7), explaining Theo's more morbid trains of thought.
End of Season 2 spoiler: In episode 12, Masas neighbour barged into Masas room twice, the second time after Masa mentions Sheridans name. With the season finale twist that Dr. Sheridan is the neighbour, its entirely possible that he forgot that he was supposed to be incognito for a moment and responded to his name, hence why he barged in twice in such a short amount of time, but was conspicuously absent from the next few episodes that takes place at Masas apartment.
When Evelyn was chasing down Tari in episode 17, why did Tari's program scroll through so many options before settling on "fight"? Because Tari prefers to avoid direct confrontation unless she absolutely has to.
In Season 2, people are seen wearing face masks and practicing social distancing. This means that Silica City, despite seeming technologically-advanced, couldn't stop COVID-19 from spreading out of control.
We know that Tari can feel pain when entering games, which begs the question: What does she feel when she dies?
When we meet Masa again in season 2, it's as he beats another player in a match. At first, the other player just seems like a Sore Loser when he accuses Masa of cheating, but considering the latter's actions in Unreal Engines when he disables Marco's arms to get the upper hand...