These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
And if you can't get enough of the cute witches being tortured, someone made an modified, hour long version of it. Enjoy...
Ensemble Darkhorse: The five Tower witches have become just as popular as the main characters. Them singing the very catchy ending helps.
Iron Woobie: Kagari. Even if she is a borderline Boring Invincible Hero, all those protecting Takamiya from the batshit insane witches must have been mentally draining.
Visual Effects of Awesome: The character of Medusa in the anime is a fairly unique case. She's a combination of normal anime-style animation and stylized CGI-cell shaded animation. It works very well. Do note that this is one of few cases where an anime actually benefits from its Conspicuous CG: Medusa is a very unsettling person.