The adult-themed superhero film Watchmen seized control of the North American box office posting the biggest debut of the year with an estimated $55.7M in ticket sales over the Friday-to-Sunday period. Directed by Zack Snyder (300, Dawn of the Dead), the R-rated film based on the acclaimed 1986 comic series averaged a muscular $15,413 from 3,611 theaters. It was the third best March opening ever trailing 300 ($70.9M) and Ice Age: The Meltdown ($68M) and the sixth largest bow for an R-rated film after The Matrix Reloaded ($91.8M), The Passion of the Christ ($83.8M), 300, Hannibal ($58M), and Sex and the City ($57M).

With a reported budget of about $125M, the anti-heroes began the weekend with a terrific $25.1M on Friday including $4.6M in Thursday night shows beginning at midnight. Saturday fell sharply by 25% to $19M while Sunday is estimated to drop 38% to $11.6M.

Expectations were high for Watchmen with many thinking it could match or even beat 300′s debut given that it boasted the same director, studio, release weekend, and rating. But the Spartan tale played broader as an exciting stylish actioner of the moment with more female appeal. Watchmen generated less interest with women and stuck mostly to a finite fan base of lovers of the comic and graphic novel. Still, the debut was impressive as it wasn’t an easy sell. Reviews were mixed and the longer running time of 2 hours and 43 minutes meant less showtimes per auditorium.

But Watchmen did enjoy a less competitive field as no studio dared to counter with another wide release this weekend. The rest of the Top 20 stole away $56.5M versus $75.5M for 300′s opening weekend. The superhero saga managed to gross more than the next 17 films combined and eked out a new record for the widest launch of an R-rated pic inching past the 3,603 sites for Reloaded from May 2003.

In the world of superheroes that jump from the page to the screen, Watchmen performed just like the first films in the X-Men and Fantastic Four franchises which bowed to $54.5M in 2000 and $56.1M in 2005, respectively. All three were based on ensemble groups of characters, had large built-in fan bases, but were not universally known heroes like Spider-Man or Batman. Watchmen had a more restrictive rating and played outside of the prime summer season, however it also enjoyed higher ticket prices.

Imax played an important role in Watchmen’s debut. 124 of the total theaters offered the large-screen presentation at slightly higher prices grossing an estimated $5.5M making it the second biggest Imax bow ever after The Dark Knight which debuted in 94 sites. That translated to a sensational average of $44,556. Imax accounted for just 3% of the Watchmen locations but 10% of the weekend gross.

Overseas where Paramount is handling the release, Rorschach and company grossed a solid but not spectacular $27.5M from 45 markets. The global bow was $83.2M.

From Rotten Tomatoes