After completing really all the game, I'd just have something to note for a possible improvement :
At first I acted thinking their was different paths for different characters (like Ian) but chose (or at least I thought I was choosing) Alex's one because of... because.
Being honnest with the choices (no backroll etc.) I got the 2/3 neutral ending (that's here that I commented the first time). When you play in the direction of the game, everything is really enjoyable, and never a moment bored.
After, I tried to make all the worst choices for Alex to get him dislike me, and I ended at -50/75. But I still got the 2/3 main ending with Axel thanking me etc etc. During this play, it sounded false, like while I was a complete asshole, Alex seemed still nice and attracted and things followed their course forcing Mark to pursue Axel. Also the points have finally not a lot of influence during the story itself, more at the end.
It could be good that earning point for a character mean more loosing points for another (after all, that works sometimes like that in real life too).
I'm glad you think of adding Ian path and some others things, that'll make the game less "closed" and not give this bad aftertast to the people trying to get out of the wirtten path.
Characters are diverses and well-balanced, it'd be too sad to not be able to discover them at will.
Another good point I saw thanks to the relationship board it that
the answers are sometimes not too obvious, like the one when Alex seems having hard time and Mark come in and can say either "I'm worried about you" or "Something's wrong, and I need to know what it is.", I picked the second one the first time guessing Alex would prefer that kind of direct question, something meaning Mark was not doing that only because attracted to him - the first answer bringing up the reason Alex is having problems.
Often in VN you have to show your affection, be with the character you want et care, which isn't interesting, here it's better.
Ps : oh also, I know it can sound strange to say that but... If possible do not use too much your own characters as avatar, I was sometimes feeling like instead of Mark it was you, Obscura, speaking, ahah.