So this is really the cherry on top of the first three seasons. The main reason this episode came out was to wrap up everything that was left hanging at the end of the third season; Takanashi's mother and Inami's feelings and Taneshima becoming the next chief.
This episode really doesn't deviate too much from the aura that the first three seasons had. It wasn't just some OVA episode that had nothing to do with the main story, in fact, this is essential to finishing up the story. It's ambience doesn't change much except for some small heartwarming scenes and the addition of Takanshi's
Nothing too special except for some of the crying scenes or reaction scenes.
They really reused a bunch of ost that have already been placed and it feels nostalgic actually if you've been following the Wagnaria!! series since it was released, but I can't give it a higher rating under good conscience.
This is where the show truly shines. Every character has their own personality and their own way of creating humorous scenes. No character truly ever gets the short end of the stick, you get a good handful of their personality and that is what makes this show great. There is a large amount of character development as well.
The majority of the comedy this show brings is like the rest of the three seasons; slapstick comedy and comedy based on misunderstandings. But, that's not to say it wasn't good. For a 50 minute episode, it was awesome.
If you watched the first three seasons, there is no reason to not watch this. It wraps everything up very satisfyingly and the ending to this episode is very heart warming.