Overall, I liked it and left me sad (I think I got the friendship ending). Since I replayed to try other endings and I spent time talking about it here, I guess we can say you did a very good job!
And now, for the unpleasant part: ***Constructive criticism***
The face of Letti is creepy when she smiles. The art is not too good, apart from Kisabel which I really liked. His voice also is very good, but the Seer voice actor is too amateur. Also, if you could voice only 2 characters in a 3 characters story why leaving out the main character? Yes, she has 10x lines but seems not much of a good choice...
I didn't like much how many times there are walls of text to describe a cool scene with no visual clue for the player, however this brought to an impacful Kisabel reveal (the normal form) which was cool and unexpected (too bad the average player will have it spoiled by the screenshots). You should consider to add some image there, something subtle thou, like just shapes.