Last week’s series premiere of “Game of Thrones” may not have lived up to the premium cable network’s massive marketing campaign, but it still remains a must-watch for fans of the series and other epic HBO dramas.

The adaptation of George R. R. Martin’s best-selling fantasy novel series, “A Song of Ice and Fire,” earned a meager Nielsen’s overnight household sample rating of 1.6, according to New York Magazine’s pop culture website Vulture. HBO’s most marketed new series of 2010, “Boardwalk Empire,” secured a 2.8 rating during its premier last September, pulling nearly five million viewers.

Nielsen data shows that while only 2.2 million people tuned into the premiere airing of “Game of Thrones,” another 2 million people watched the show’s first two encores, according to Entertainment Weekly. Official data has yet to be released from Sunday’s airing of the second episode of “Game of Thrones.”

“Thrones” is the latest of recent HBO offerings that have failed to meet ratings expectations. “Mildred Pierce” – the five-part miniseries directed by Todd Haynes starring Kate Winslet and Guy Pearce – posted ratings as disheartening as its Depression-era setting. According to Deadline.com, the March 27 premiere of “Mildred Pierce” pulled only 1.3 million viewers.

Despite initial ratings lower than their other hit series, HBO renewed “Game of Thrones” for a second season last Tuesday after airing only one episode, according to CBS. HBO appears to be just as confident in “Thrones” as they were in “Boardwalk Empire,” since they renewed the Prohibition-era crime drama starring Steve Buscemi on the Tuesday following its premiere in September of last year.

“Thrones,” which tells the interwoven violent power struggles of the mythical Seven Kingdoms of Westeros, seems to stay true to HBO’s holy trinity of show elements: sex, violence and gore. The first two episodes featured plenty of all three, with graphic beheadings and steamy whorehouse scenes clearly flaunting HBO’s status as uncensored television.

Sean Bean, who plays the main character Eddard “Ned” Stark, is no stranger to roles set in fantasy worlds like Westeros. Bean traversed Middle Earth in director Peter Jackson’s interpretation of J.R.R. Tolkien’s “The Lord of the Rings” series as the warrior Boromir.

He also played the legendary Greek king Odysseus in the 2004 interpretation of Homer’s epic poem “The Illiad,” the mighty god Zeus in “Percy Jackson and the Olympians: The Lightning Thief” and voiced the Emperor Martin Septim in the 2006 fantasy role-playing video game “The Elder Scrolls IV: Oblivion.”

While Bean has been solidly typecast into these roles, it still makes perfect sense for him to portray characters like Stark in “Game of Thrones.” The English actor attended the Royal Academy of Dramatic Art and was a member of the Royal Shakespeare Company. Bean still uses the Shakespearean diction and royal eloquence of his career’s earlier roles in the fantasy characters he portrays today.

Critical reception for “Thrones” has been mostly positive, with Tim Goodman of the Hollywood Reporter praising “the crowd-pleasing elements of war, honor, pride, lust, power and … humor” that are supported by “exceptional storytelling, strong writing, superb acting and some stunning visual effects.”

While it may be slightly premature, Entertainment Weekly and L.A. Times critics are already discussing Emmy nods for Peter Dinklage and his portrayal of the rude Tyrion Lannister.

Whether or not the praise for the series lasts and casual viewers continue to tune in, Martin’s novels have enough of a hardcore fan base to keep the series alive for many more episodes. With HBO’s announcement last week, the network’s executives are willing to bet the same, at least for another season.

The third episode of “Game of Thrones” airs this Sunday at 9 p.m. on HBO. The first two episodes of the series are now available on demand to current HBO subscribers.