Indeed what you have put into the game is amazing, I want more of those flashbacks that was an epic moment that I never expected to happen.
Well if you like I could draw a few animations of characters that you could take idea's from. I just dislike the helmet it looks strange (and rather cheap) It would look much better if Id male had a baseball cap and Id' female had longer flowing hair that would make her look more like a young woman, Not a lesbian ^^
Oh and about the personna of the characters. I would love for Id to behave the same way, but as the game goes on become a darker and darker character, until about chapter 8 when id hits his/her darkest and maybe turns to violence/crime to solve their problems or could go totaly crazy and maybe even short curcuit. Then after than moment someone or something a vision or a doctor could help ID .. I just think slowly her/his memories should return and at the start they make Id angry, maybe even seek revenge. but then as more information comes to id and she/he gets help then the personality could change and become more uptempo. I dunno what your planning, new characters or anything I just am a big fanfiction writer and my reviews are good :P so thats why I think character develpoment would come 2nd nature to me