"If Sunday night's two-hour return episode of Mad Men ended after the first four minutes, it would still put the show in contention to win its fifth straight Emmy as the best drama on television," says David Hinckley at New York's Daily News. That's tantalizing news for the AMC drama's passionate fans who've been starved without a new Mad Men episode for 17 months. (Tense negotiations between the network, studio, and creator Matthew Weiner led to a production delays.) When we last left Sterling Cooper Draper Pryce, the ad agency's creative overlord Don Draper had startled everyone by proposing to his new girlfriend Megan, Joan had decided to keep Roger's baby, and the suits were reeling from the loss of their biggest account. Thanks to Weiner's polarizing plea that critics reviewing the premiere suppress all spoilers, few plot points have leaked, but the press still found much to (vaguely) enthuse about. Here, seven talking points:

1. Don is getting older
Don is now 40 and reeling — in enthralling ways — as time seems to pass too quickly, says Tim Goodman at The Hollywood Reporter. Credit Jessica Pare as his maybe-fiancee, maybe-wife, maybe-ex-girlfriend Megan (no one can say, because of the spoiler moratorium) with bringing out new shades from the aging Draper, says Hank Stuever at The Washington Post. She's the pivot point between the "psychological gloom" that permeates Sterling Cooper Draper Pryce and the emerging "psychedelia" of New York's '60s culture. "In just a few scenes, she becomes Mad Men's most watchable new asset."

2. We still want Don to be bad
Don Draper may be the most complex, fascinating lead character ever, says David Wiegand at the San Francisco Chronicle. He's a "mass of contradiction and mystery," even more so as he grapples with age and mortality. (When he asks his son how old he will be when the boy turns 40 himself, Bobby replies, "You'll be dead.") Played broodingly by Jon Hamm, Don is a "fundamentally decent man doing awful things that are almost beyond his control," says Chuck Bowen at Slant. Audiences may find themselves appalled as they forgive and "quietly [relish]" his behavior.

3. Burning questions abound
Mad Men is so addicting because it's impossible to predict how the characters are going to behave or why, says Linda Stasi at The New York Post. After the abrupt coupling of Megan and Don, we're left to debate whether she's really in love, or just needs a career boost — whether he's finally happy or just briefly sexually gratified. Meanwhile, will Joan's Army doctor-husband figure out the baby isn't his? Will Pete's blind ambition get the best of him? Seeds of several answers to each of these questions are planted in the premiere — which is exactly what makes Mad Men so "insanely riveting."

4. The characters haven't changed too much
Though critics have obediently kept mum about the plot, they hint that most of our beloved characters are back in classic form. The premiere "is a valentine to fans," says Maureen Ryan at The Huffington Post, in that Roger is especially quippy, the decor is extra mod, Peggy is as awkwardly ambitious as ever, and Joan continues to dress down her male colleagues.

5. It boasts one of the best Mad Men scenes ever
Not all plot points have been suppressed. One pivotal scene — a surprise 40th birthday party thrown for Don by Megan — is apparently a squirm-causing doozy that propels the series forward. It's "one of the most amazing and contextually weird scenes Mad Men has shot," says Goodman.

6. The new time setting re-invigorates the series
Braving the wrath of Matthew Weiner, Stuever dares reveal that the new season does, as rumored, take place in 1966. The time shift and the new sociopolitical context add a "subtle" new vibe. It's almost as if we're now watching "Mad Men — in living color." Literally: "I see... blocks of trippy color. I see the first hints of plumage on the men. Don and Megan's new high-rise apartment is a splash of white carpet and zebra-striped pillows." The sudden explosion of color clearly signals that these characters' "world is about to burst, as we've always known [it] must."

7. There's no Betty
Where's Betty Draper? The most divisive, arguably unlikable Mad Men character does not appear in the premiere at all. Perhaps it was wise of Weiner to hide Betty from us for the first episode, says Stasi. Absence truly does make the heart grow fonder, and, despite her typically divisive nature, her conspicuous omission from the episode "makes us miss her and wonder about her even more." The biggest burning question: "Is she still so crazy?"