Really, the only character I think he could overly-like is Yuka with the whole "youkai moe" thing. :3
Honestly I always found the "X character is a slut" meme humorous. I mean some of the main proponents are Sakuya fans who conveniently forget the fact that she starred in 5 straight games! (TH 6, 7, 8, 7.5, 9) I really think it's just him doing what he wants, with the characters he wants. It seems to me, though, that he's putting a lot more thought into things since MoF, since the stories and settings seem to flow much better than 6-8, which would explain the recurring characters.
Cirno as a character I've always liked. Not loved, but she always struck me, as Tengu just said, as child-like and overconfident. Though canonically stupid, it's born more out of hard-headiness and a desire to prove herself than pure retardation. Which is why I like stories like Cirno-chan is the Strongest and Thank You Cirno-chan, which imo display this likable quality of her.
As for the game itself, I have no idea what the engine apparently is based on, just that freezing (and blowing up?) bullets levels her shot. What the shot does I can't tell. Looks interesting though. I suppose I'll keep an eye on it, I really could use a short pick-up game.