Did Memories of Alhambra writer forget about Marco?

As we know, the fact was, that all of the NPCs that were previously real players and had been killed are bugs. And all the bugs has to be deleted with the Key to Heaven. 

Let's summarize this. 

Jin Woo stabbed Cha Hyun Seok (Mr. Cha) as the first  NPC - his enemy.

Then he stabbed Cha Byung Joon (tester01 (or something like this)) as his alley, which appeared because the alleys may appear when he is in danger. 

Then his best friend, colleague Seo Jung Hoon (City Hunter) who apparently appeared because he was in danger.

Then he gave the Key to Heaven to Emma, to delete him as well. 

The rule was, all the bugs has to be removed to let the game reset. But he didn't kill Marco. Marco has no connection to Jin Woo thus he didn't appear. Se Joo couldn't delete Marco as well, because didn't have the Key to Heaven. 

Is there a hidden reason to this? I was assuming maybe second season will be produced. 

Or did the writer simply forgot about it? Is it easy to forget this important fact? Marco had been chasing Se Joo as well as Mr. Cha been chasing Jin Woo. 

What are your thoughts about this?

I loved this drama to pieces, it completely took me by surprise and while I don't dislike the ending, and would definitely watch S2 - I do have some kind of huge questions that keep nagging at me which I think have been asked already lol but I'm going to ask them again!

Is someone able to explain to me why Marco disappeared and the game reset clear of bugs when Marco was not dusted with the Key to Heaven?

And I have another question about why JinWoo turn to dust when he was not part of the initial bug - meaning he shouldn't really have been a bug to begin with as he was a successful game player who had become the highest ranking 'Master', right?

If the initial bug was created when Marco stabbed SeJu in the presence of Emma who tried to neutralize the violence as it is not meant to occur within a 20m radius of her, then shouldn't SeJu also be a bug and therefore need righting by the Key to Heaven as well?

Ergo, even if JinWoo's physical body is in an IRL created instance dungeon (as SeJu suggested - possible S2 plot) waiting for someone to become the Master to save him, his ID still shouldn't have been turned to dust, right?
We know he can't be an NPC as his physical body isn't deceased and that he also has control over his actions to shoot and help the players in the final episode, and even if his ID Jinu was destroyed with the Key to Heaven, logically he would have been able to keep his high level gun as it was custom content created for him by Yang and would have been saved from the map reset.

 But the question is this: how does he keep his 'Master' status and corresponding instance dungeon if his ID was destroyed by the Key to Heaven?
Unless the instance dungeon was destroyed with the reset and that is why he appeared to the public at the end - but then how does he still have access to log in and out of Next without the lenses, as part of the bug was that he was constantly automatically logged in whenever an enemy appeared when this should have also been fixed by Emma during the reset.
If he had gone to buy the lenses he would have definitely been noticed by someone and he would have an ID - which the players in the cafe said he did not.

...Right?