What I understood is that cause he changed the timeline by saving him, they never got to meet in the timeline…
Wait, hahah you do have a point. But think about it that way, the timeline he saved him in still exists, but he was supposed to die, right? At the start before he went back to save him (that timeline) , they didnt show us what they did together (in the timeline where the story starts, the future or whatever) , for example, like we didnt see the portrait that they drew together, hence maybe they did draw it in the past, that is why it is there you know? At least that is what i think.
As for the friend, i was thinking about it, and the only answer i got is that, maybe its a different version of himself. Ummm how would i explain it, have you ever watched rick and morty, they talk about how multiple you live in multiple timelines and all of those yous are not aware that they exist. same thing, maybe there is more than one him, hence he didnt know what happened. Hahaha :P
they left so many things unfinished and unexplained, like i know i am dumb but nit that much to not understand…
What I understood is that cause he changed the timeline by saving him, they never got to meet in the timeline where they are both in. When it was time for them to meet, both timelines crossed, hence the scenes where they are both in the same place but never get to see each other. As for the colour blindness thing, I think it's just to explain the fact that Jeoinshi got hurt multiple times, like the first ever car accident when crossing the road. Now, for me, the only confusing thing is how the friend ( the 3rd one ) doesn't remember anything, or how he doesn't know where Jeonshi is (in the future I mean), or how is he even besties with Woojin if he disappeared? All in all its the cutest!
As for the friend, i was thinking about it, and the only answer i got is that, maybe its a different version of himself. Ummm how would i explain it, have you ever watched rick and morty, they talk about how multiple you live in multiple timelines and all of those yous are not aware that they exist. same thing, maybe there is more than one him, hence he didnt know what happened. Hahaha :P