... Actually, that's a very smart way of hiding the fact that the external game is a game, since you'd be interacting with a computer inside of the computer... and so then the game mechanics are no longer exposed and cannot attack one's suspension of disbelief.
In The World Ends With You, the protagonist wakes up with amnesia in the middle of Shibuya. He's enrolled into a mysterious "game", where every day he is given an arbitrary objective (such as reaching a certain location, solving some puzzle, defeating a boss) and if he fails, he will be erased from existence. He is impeded in this by invisible walls that arbitrarily block his way into some parts of the city. Sometimes these are guarded, with the guard requiring that you complete some arbitrary mission (bring me a hot dog, kill a bunch of enemies, etc.) in exchange of removing the wall. And then you go shopping for clothes.
You know, like
every JRPG ever except more meta.
But yeah. We're supposed to be talking about Andrew's webcomic here. Terezi is being pretty dense. Maybe if she executes Vriska for the wrong crime, the death won't be just enough and she'll just respawn?
Anyway,
all the trolls are going to die, as per Sollux' doom prophecy. The question is mostly what counts as "death". Terezi's probably safe, since she was bitten by Kanaya. Gamzee or someone will gruesomely murder her, and she'll return as a rainbow drinker. Karkat is protected by time shenanigans for now, and we saw Gamz looming over him in the Zillyhoo flash, so I'm guessing he's dead and going to return in some manner. Knight of Blood powers making him a rainbow drinker too?