Ahahaha yes this is going to be so awesome. I've wanted a Shoot the Bullet sequel for ages now.
Comments on ZUN's artwork: Ehh, not as good as UFO, but I can still take it. Elf ears are a bit strange, but I guess I can handle it.
Also YES NEW SPELLCARDS. Especially for those midboss characters like Shizuha (and maybe spellcards for Momiji too? Gasp.) The third screenshot (the one with the lasers that cover the sprite) has a spell card background similar to Minoriko's, so it looks like she'll be in the same level as Nitori (as they have the same photo numbers.. or am I overthinking this?).
Looks like there are new mechanics coming in to play, or the REST 4 message in the last screenshot (curvy lasers) is just a different version of an old mechanic.
Also, the game name: abbreviating it leads to DS, which is very commonly used in other areas which may lead to confusion, especially since that one site we all know and love has the same abbreviation.
I'll use DbS as an abbreviation :V