I haven't watched the anime. I did play the game and while parts are vague some parts are vivid.
Shiki hit it on the head that the decision choice is you have timed choices that boil down to yes, no or do nothing actions and that you can't avoid hurting anyone since all the choices have repercussions on other characters and you have little time to think what they could be.
But with that was my problem with the game, I found Makoto annoying with his attitude and the options you had to take were down to Makato's failings not mine. I remember thinking to myself the choices limited me to something I wouldn't wanna do, but in essence I guess that is how the game plays and is meant to be a dilemma drama about young love. I played it and felt rather annoyed with the character and how he is. I didn't get the feeling me and Makato was the same.
I felt why is the prick not suck it up and not let the issue get out of hand and sort himself and these girls out rather then being a such a indecisive twat. My personal approach was that I'm with Koto and I wouldn't have fucked around with Sekai no matter the BS but Makato doesn't give you a choice in that matter since his selfish and wants both girls and won't tell them how it is.
Though you may think I completely dislike the game I don't, it is unique with the anime/VN approach and I can respect it is trying to show something interesting, it's just these sort of emotional roller coaster love stories don't gel with me when I find the MC so annoying.
I say play it and see what you think yourself it is well worth the time.