Broadcast network shows have largely done away with opening title sequences. The artform still exists on cable, thankfully, because when done well, a title sequence tells you all you need to know about what a show is like. Think Tony Soprano driving from Manhattan to his McMansion, or Dexter Morgan going through his surprisingly violent-looking morning routine.

Showtime's family dramedy "Shameless" has a terrific opening title sequence - albeit one that you won't see on the pilot episode that premieres tonight at 10. (TV pilots are often title-less for some reason.) The sequence places a fixed eye on the lone bathroom shared by the sprawling Gallagher family. Alcoholic dad Frank (William H. Macy) has to be dragged out of there by eldest daughter Fiona (Emmy Rossum) so she can go to the toilet, and then we watch Fiona and her brothers, sisters, friends, neighbors and everyone's assorted boyfriends and girlfriends use the bathroom for both its intended purposes and many others, from sex to the toddler using the toilet to brush his teeth.

That's "Shameless" in 30 seconds or less: messy, overcrowded, unapologetically frank and, at times, darkly funny.

Frank is a lost cause - a pathetic, lying drunk who's often just another piece of furniture in the cluttered house - but is still a more useful parent than the kids' mom, who long ago skipped town. So Fiona raises her siblings in part, and in part, they all raise themselves, because they have no choice. While Frank's busy drinking away his shady disability check, Fiona works a series of odd jobs that largely involve her filling in for friends who have their own problems. Teen genius Lip (Jeremy Allen White) is an expensive tutor, and will also take the PSATs for you, if the price is right. Youngest daughter Debbie (Emma Kenney) steals coupon inserts from their neighbors' newspapers so the family can afford to buy groceries. While the older kids are busy pooling their cash to pay a utility bill, Fiona looks at one of the young ones and says, "You're almost nine; you're going to have to start pulling your weight."

But where this material could seem dark and depressing, "Shameless" is a happy show - more a one-hour comedy (albeit more pleasant than laugh-out-loud) with serious elements than a drama with occasional jokes. The Gallagher kids don't have much, but they have each other, and that seems more than enough. When Lip can't afford to take his girlfriend on a real date, they camp under the elevated train tracks and enjoy watching the trains roar overhead, looking for all the world like two kids having a blast on a roller coaster. When none of the older sibs are available to take care of baby brother Liam, Debbie happily straps on a Baby Bjorn and carries him to school for Show and Tell.

That us-against-the-world mentality, and the characters' optimistic approach to their dire circumstances, comes from the mind of Paul Abbott, who created the long-running British original. American producer John Wells brought Abbott over to write the remake, and the first two episodes are very faithful to the respective hours of the British show.

At times, it feels a little too faithful. It's been a while since I'd seen the British pilot, but there's definitely a sense in the remake that this is material written for other actors, in another culture, and transplanted fairly literally to the slums of Chicago. Some of the actors fit well into the pre-existing templates, particularly Rossum, who's feisty and strong and sexy and very much holds the show together as well as Fiona does the family. (Fienberg called it a career-redefining role on our podcast, but as this is the first thing I've ever noticed Rossum in, I just considered it one hell of a debut.)

Macy, on the other hand, doesn't entirely work as Frank. The character seems most interesting when he's either being an unconscious prop, or in a brief, dark scene in the second episode where Macy is briefly allowed to play him as something other than a wacky, disappointing but lovable rogue. He's the biggest name attached - well, him or Joan Cusack, who has a very Cusack-ian supporting role as the eccentric shut-in mother of Lip's girlfriend - but it's usually hard to look at Frank and see anything other than a fine character actor diversifying his resume.

I also don't think it's a coincidence that the third episode, which deviates the most from the original material, is also the most consistent, engaging and funny of the three I've seen. Regardless of what Showtime's new "Episodes" (which, in an odd coincidence, airs right beforehand) will try to tell you, trans-Atlantic remakes tend to work best when they don't slavishly copy their predecessors, and the more Abbott and Wells let the Gallaghers of Chicago distinguish themselves from their counterparts in Manchester, the better off "Shameless" will be in the long run.

Still, even if Macy isn't a perfect fit yet - nor is Justin Chatwin, as Fiona's new boyfriend Steve - the performances by all the kids, and the sense of the world that Abbott and Wells create, are so strong that I want to give "Shameless" a while to see if it can establish its own voice.

Alan Sepinwall may be reached at sepinwall@hitfix.com