rereading this manhwa and how can he remember the start of the game that he played like 11...

Pretty sure he says sometimes in his dialogue that he would delete characters or reset games to try to find different ways and different secrets so i think thats why

I think you missed sumn lol the game is really hard pretty much mission impossiblr so he replayed the tower over and over from bottom to top for 11 years. He's basically a fanatic so ofc he remembers everything about it from start to finish.