It’s hard to keep track with new characters when they keep changing clothes the next time you see them. Unless each character has distinct looks, for example, Echoes, it’s really hard to recognise them. Plus, throwing out names to introduce new characters only adds more confusion.
We don’t really care enough for the characters. The show only jumps around from plot to plot without giving us a reason to care for them. This is a typical anime adaptation flaw where studios wanted to compress the entire story with their limited episodes and failing to build the characters as a result.
Non-linear story structure
It doesn’t really make sense to tell us that Boogiepop is leaving because she defeated the enemy on the first episode. This only spoils the suspense you’re building up for the succeeding episodes. Case and point, Nagi Kirima on the last scene of the first episode only ruins the surprise on the third episode.