What I Liked: The colour schemes. Great premise. Set design for Ortus. Animation itself was above average (aside from inbetweening - average marks there) and quite stunning. Final episode was engaging, and involved one successfully executed twist.
What I Didn't: Where do I start?! The premise wasn't fulfilled. The Gravekeepers were a let-down. First story arc could've been longer and less full of holes. Logic holes in every simple damn arc. Also invoked the "Pistols have Unlimited Bullets" flaw. The Goran Acedemy arc was a superfluous diversion. The OP and ED. Ai was almost entirely static. Final arc could've been shortened by an entire episode, and was ruined by trying to wring out as much empathy and "feels" as possible. Keiji Fujiwara couldn't stop mumbling his lines as Yuri / Julie. We're supposed to believe that God has abandoned the earth... but is still granting wishes like some genie?
Final Verdict: Despite being quite a beautifully-rendered series, Kamisama no Inai Nichiyoubi discards its intriguing premise early on and unfortunately degrades into a pretty but ultimately vapid series about the fantastical adventures of a little girl. If you want the perfect example of style over substance, this is it.