Freud Was Right: As mentioned on the Does This Remind You of Anything? trope of the main page, Key Princesses act rather . . . weird when having keys plunged into their chests. Shown by Arisu in the manga, it apparently works if you insert it in the back too.
Shocking Swerve: In the anime, Liddell kills Takion out of jealousy and she wants the power of the Never-Ending Alice for herself.
They Wasted a Perfectly Good Plot: Arguably. Despite ostensibly being about a There Can Only Be One scenario, the anime and manga focus mostly on the characters, only actually showing a few of the fights (most of which are fairly lazily done). You can actually find artwork of the other Seekers of Alice who never made a full appearance around, and see profiles of them on the show's site. Sort of a shame, since a lot of them seemed like they'd make fairly interesting battles.