This rating is for 1.2.4i
Music - I don't listen to game music
Voice acting - very good, aside from maybe Europa. Her accent makes her sometimes hard to understand for not native english speakers or those used to it.
Art - a few full CG, very well done. Animations are hit or miss on transitions between loops, but good quality overall.
Gameplay - worst part of experience. Game itself is fine, but controls are a bit clunky, especially during scenes and dialugue. there is also quite a few bugs. Nothing gamebreaking, but visual errors and a few times quitting ongoing scene moves you to gallery.
story / dialogue - well written. Characters have personality, but there is too little of it to fully flesh them out. Ending feels unfinished. Possibly continuated in nextchapter ? Still, it could use something to signify to player that they 100% the game.
Overall - Bugs aside, there is a bud of high quality game there. The biggest problem is that it remains a bud. I haven't checked the rest of the series, but as a standalone game it feels cut before reaching full potential. Also, scenes with voice acting lack options to skip a line, accelerate or show text. This may be an issue for people that don't like half a minute of slurping noises, like myself.