I have to warn you, I've found the cause of most of the fails in vipassanaa practice :
If suffering isn't great enough, the will to end it will be weak, and so there'll be no concentration.
If suffering is too great, the will to end it will be strong, and so concentration will be correct.
However, when concentration arises, the previous thoughts are stilled, and so it is impossible to remember the Dhamma while practicing true vipassanaa.
So how did I succeed ?
As I said, the anime's rules are very similar to the samsaraa's rules.
So the "deletion" of the protagonist I was attached to reminded me of nibbaana.
"her nibbaana was the cause of my suffering" : this is what I understood.
"she'll never come back, so I must end up sadness"
"I have 3 options : either I forget her, either I just keep her in my mind, either I realize nibbaana"
Whereas the 1st two options are ultimately useless, the 3rd option rouse because I precisely though of nibbaana earlier.
"nibbaana is the highest peace", "nibbaana" is the lack of craving".
And so the Fruit followed the Path, which itself followed insight.
Insight is not the Path, insight is what leads us to the Path.