That’s my swingset, and that’s my sandbox. I’m not allowed to go in the deep end. And that’s where I saw the leprechaun.— Ralph
In the very first scene, a three-eyed crow flies past. It caws as we move into a sweep over the power plant - this is the same crow we've heard from every past establishing shot of the plant.
From there we go past the tire fire and to Springfield Town Square, where Kearney and Jimbo saw off the head of Jebediah Springfield. It lands on Ralph Wiggum.
Next we follow a road towards Springfield Elementary. Look out for: The
Android's Dungeon and Baseball Card Shop, Phineas Q. Butterfat's Ice
Cream Parlour (with Marge-esque cone on top), Lardlad Donuts (the
three-eyed crow sits atop the donut), and a billboard. Initially the billboard
Krusty: Now Doing Funerals but it has become a new running gag,
changing every episode.
This is still largely the same; however, notice the framed photo of Homer as an astronaut on the wall. When Bart flies off the school steps, he lands on a pile of leaves, which it turns out are covering Barney. He lets out a belch as Groundskeeper Willie shakes his fist.
Homer still leaves work with plutonium stuck to his back. In the background, however, Burns and Smithers are absent: instead, Lenny and Carl try to add a day to the "no accident" count, but Lenny falls off the ladder.
Patty & Selma buy a trolley-load of cigarettes. When Maggie is scanned, the running total on the checkout doubles from $243.26 to $486.52 (i.e. she 'costs' $243.26), as opposed to her previous price of $847.63. Matt Groening stated the original figure was the monthly cost of raising a baby in America - does this mean that 20 years later, it's much cheaper?
Among the magazines are Donut Fancy, Anxious Mother and
Peephole. An advert on the back of Marge's magazine reads
Krusty. Marge is buying Frosty Krusty O's, Mr. Sparkle, and
When Maggie is plonked in the trolley, Gerald (the monobrow baby) is in the neighbouring trolley. They shake their fists at each other.
Back at the school, several new kids have joined the band practice:
A photo of Bleeding Gums Murphy is on the wall behind them. Sherri and Terri are playing handheld consoles instead of flutes. Lisa does her usual solo, but now she pops her head back round the door after leaving.
Otto catches and eats Homer's plutonium when Homer throws it out the car.
As Bart skateboards past the shops, there are some character changes. Sideshow Bob swipes at him with a machete. Bleeding Gums Murphy and Jaques are no longer present, and Barney has been replaced by Comic Book Guy (since Barney was busy sleeping under some leaves!). Helen Lovejoy, Apu, Moe and Chief Wiggum remain - though Apu is with his eight kids (previously he was walking a dog). Disco Stu, Crazy Cay Lady and Big Rich Texan are new. (Why those three characters were chosen I'll never know!)
As Bart skates across the road, Hans Moleman lifts the manhole cover and pops his head up from the sewer. Marge runs over the cover, pushing Moleman back down.
Maggie still appears to be driving the car for a few seconds, however, on the pan
out, Grampa is also in the car. When Marge and Maggie toot their horns, he wakes
up startled and his teeth fall out. Also note Maggie's upgraded
brand steering wheel.
The super-fast pan across Springfield appears to be more-or-less the same, but
there are quite a few differences. A Duff blimp flies at the far left of the
El Barto graffiti is on the wall.
On the driveway, instead of being comically chased into the living room by Marge's car, she now hits Homer and he goes flying through the wall, leaving a cartoony outline.
The couch gags appear to follow the same format - though the first HD episode's couch gag in extremely long and convoluted. The notable change here is that the family are now watching a HD widescreen television - though it falls off the wall and smashes!
The second HD episode, How the Test Was Won, made a few changes to the opening sequence:
it's dark!instead of
hey!instead of belching when Bart lands on him.
whoaas Bart skates past (previously silent).