For me this game has earned a 5/5 rating.
1st, the Characters:
MC is a half Vampire, with two human childhood friends and two full fledged vampire (half-)sisters. While vampires and humans don't really get along well, these people try their best in overcoming their cultural differences and even discover similarities between themselves without being bland about it.
Each of the characters has their own personality and looks, as well as motivation that drives them forward throughout the story and their interactions with MC. That means, the characters actually have some depth and personality and are not only fuckable eye-candy.
2nd, the relationships:
With Sun Breed being classified as an Incest game, obviously there is something going on between MC and his vampiric sisters. The refreshing part about this is, that they already are in a relationship with each other. This is actually a welcome change for me, as you don't have to seduce them first and try to get in their pants. You are already in there, and they want to keep you there.
Regarding the human sisters, you also have a very intimate relationship with them too, albeit not as sexual as with your own sisters. This is a welcome change too, as it doesn't force sex scenes on you without there being an understandable progress in relationship.
The speed at which the relationship between the characters progress is believable and doesn't let you feel overwhelmed by how much information gets released at once. Getting to know the characters backstory, you actually feel connected to them, like in a good book.
3rd, Graphics:
The renders are looking good, which each character having their own unique dewign. There are varied locations, which are woven well into the story.
Aditionally, and this is me being biased, but I absolutely love readheads, cuddling scenes, belly buttons and belly button piercings. So I absolutely love what I see here.
An honorable mention: I have never seen a bug in this game. No error report, no crashing for whatever reason. Maybe I got lucky, maybe this game was actually programmed well, I don't know and I honestly don't care for the reason. However, this is one of not even a handfull of games I played here where these things didn't happen, so i thought I should mention it.