I'll keep it short, like the characters and the episodes
Great seiyuu: M.A.O,; Takahashi Minami (no, not "that" one, the other one); and Izawa Shiori - all of whom I adore and who deliver the snappy dialogue well (subs are OK, too.)
Fun premise: someone already mentioned the L.N. series, so I'll leave it at that.
SEGA lovers: sigh, the good old days.
Short episodes: (so far) It paces