Bolt1984

Maybe I don't know how to rate specials, but whatever. This was very delightful to watch. With it all totaling up to just a mere 7 minutes, you'll end up wishing there was more. These specials were delightful to watch and provided for some laughs at just how ridiculous it was. I found this more enjoyable than something like Sword Art Offline (which just gave you a bunch of useless information with boring character interaction). When I finished the main series I was a bit worried to see how this would be, but it was a delight. I'm happy to have seen this.

Shirogari

Henneko BBS consists of 13 short clips each around 40 seconds and focus on Tsukiko eating and Yokodera being a pervert. Even though they were initially used as advertisements they aren't very representative of the anime and should not be used to decide whether or not to watch the anime itself. Considering it takes less time to watch all 13 episodes than a single episode of a normal anime it's not a big commitment and can be fun to watch if you liked the anime and want to see a bit more of the characters. However don't expect too much because of the very limitedlength of these clips.