Slice of Life.

So, what's going on in this one that's got everyone so hyped up?

-Cranky and Matilda are getting married and due to a mistake the date has been pushed up one day.
-Derpy's the one who hooked up Cranky with the invitation service and got him everything at half-off by going with an amateur.
-Featherweight and his setup at the Foal Free press was said amateur.
-Doc is Derpy's friend and he's a science buff.
-Vinyl still doesn't talk.
-The Lebowski ponies make their own wardrobe in addition to being bowling enthusiasts. (and nopony knows what a man is, man)
-Octavia does sound like her Equestria High equivalent.
-Bugbear is a single creature, not a D&D race. It also looks like a bear-y Beedrill :)
-Amethyst Star used to be the main organizer in town pre-Twilight.
-The florist ponies still exaggerate over eveything. The Horror! :)
-Lyra and Bon Bon are bff's. Lyra's magic field is yellow-gold. Bon Bon's real name is Sweetie Drops and she used to be a monster hunter but her organization was disbanded when the Bugbear escaped Tartarus years ago. She's been in Ponyville incognito ever since, probably as part of a witness protection program. Also, her main training appears to revolve around the ability to vanish into crowds. pretty darn cool.
-"Celestia demanded complete deniability." -this sentence. Damn, this sentence.
-Doc does the whole Fred Flinstone twinkle toes bowling thing :)
-Steven Magnet and Cranky are old buddies and went off on adventures. * Magnet is fabulous and funny as ever but being a foil with the whole "the wedding is everything"... was either horrible or awesome depending on taste.
-Vinyl and Octavia are roommates (or a couple) living in a half-and-half house (that's kinda weird). The duet was pretty cool (classical music and technology aren't antithetical folks). Then they use the Vinyl's rig as a vehicle with Octavia plays through it the whole way. * They crash through the most interesting ponies from Perfect Stallion (with Buttons spinning on the turntable-so cute) and crashing through the delivery ponies (suggesting that Derpy lost her job hauling for Crafty Crate but Sunshower Raindrops didn't).
- Gummy has an existential monologue, meaning maybe Pinkie isn't projecting when they have conversations.
-Celestia and Luna argument :)
-Shining is a crybaby :P (liquid pride)
-Steven Magnet pays the mustache forward :)
-Derpy locks the Mane6 out :P
-Surprise Changeling in the back scaring the foals lol.
-and finally, Lemon Hearts took the twilicane.

All in all the story feels a bit like a fanfiction. You can't take it seriously and as it's written it's a story that's not supposed to be taken seriously. It's supposed to be a fun story.
Of course, some parts are just too much compared to others. Bon Bon is over the top - why would an irrational monster be after her? The scene needed a different kind of exposition. And the grappling hook? She could have just walked outside into the crowd - but still good.
Steven Magnet's presence as a friend of Cranky's stretches my suspension of disbelief.
Using the turntable as a vehicle, deliberately since they burst it out from their house, with Octavia playing base the whole way is imo too much. It's a cool image for a short but as part of a full episode it's just too silly.

But those 3 details are just the ones I'd dismiss as ambiguously canon. All in all, it was a wonderfully fun experience and made me feel like I was watching an old Simpsons episode, the only thing in recent memory I can think of with a comparable cast.