Word of God has stated that it was intended as a deconstruction of self-insert tendencies.
Angst? What Angst?: The tendency of this trope to show up in self-insert fiction where the author avatar just teleports into their world is heavily deconstructed. Almost as soon as he realizes he's in the Mass Effect universe, Art begins wondering what's become of every person he's ever come to really care about, and about what they must be thinking in turn. At first, Art brushes off the angst under the pretense that he can head home via Virmire. However, by the time he gets to Virmire he's truly gotten to know the Mass Effect cast, and so he begins greatly second-guessing himself on his desire to go home, torn between losing one group of people that he cares about to gain another. When he finally decides to attempt to go back to his home dimension, it ends up not happening thanks to Shepard saving him at Virmire. After that, the angst comes for him with a major vengeance when he realizes that he'll never see the family and friends that he knew for basically his entire life. Even worse is that thanks to the cover story he made to avoid suspicion, he basically can't tell anyone about why he's really angsting and has to hold the real reason for his angst in. As if that wasn't enough, Ashley Williams, the woman who taught him everything about how to use military-grade weaponry, a reasonably good friend of his, and one of the people he was trying to save from her probable in-game fate on Virmire was the one who died. Art blames her death on himself for not being able to convince Shepard to save her instead of him. After the obligatory One-Woman Wail, he spends an entire chapter locked in his room while moaning about his predicament. He gets better thanks to Tali.
It gets worse. In Mass Vexations 2, he finds out that fate would not let him die on Virmire, so he basically spent all that effort for nothing. However, Ashley didn't die, she went space-travelling the way he did, so it's not that bad... technically.
He somewhat expresses this the first time he kills someone, but he stops dwelling on it because it's not really a good situation for him to space out.
Follow the Leader: There were relatively few Mass Effect self-inserts before Mass Vexations was originally posted. Afterwards, the section at first slowly and then very quickly became flooded with quite a few self-inserts.
Fridge Horror: In combination with Spellbinding Radiance: Art was hoping to use Virmire to get home. However, when Ash dies at Virmire, she winds up on Tellius within Spellbinding Radiance's continuity. If Art had been killed on Virmire instead of Ash, he likely would have died, or not been returned home at all.
It goes even further. It sounds like Spellbinding Radiance uses the same method of getting the hero to the canon universe in question, aka, The person dying and entering the Fade in the right area so that they're reshuffled dimensionally. It's outright stated that Art's teacher and Ashley Williams did the same thing, so it's not a unique thing. If this is the case, than how many other Self-Insert fan fictions are the result of the death of the author?
Holy Shit Quotient: Chapter 17 of Mass Vexations 3. Nogond is dead and has been replaced by an impostor, Daro'Xen has some kind of devious plan in the works, Tali is missing, there's a Reaper on Rannoch, and Legion's learned how to use 'That's what she said' in conversation.
It Got Worse: The impostor is one of the Migrant Fleet's most dangerous exiles, he raped Tali, Legion nearly died and the Reapers know about the Fade.
Pandering to the Base: The (occasionally forced-seeming) over saturation of references can be seen as the author trying to rack up some nerd cred.