Tadano has a round head in this oneshot. And Komi-san is less edgy-looking as well. Visually speaking it's more logical/natural. Although, i'd say the artstyle used in the series is more unique though. Can't decide which is better.
Story-wise the intro is definitely better in series. Here she just talks when they are alone but i loved the blackboard version way better.
In series i find Hitohito's name quite silly but that's not that big of an issue, lol.