Oblivion, the science fiction movie that is based on a Radical Studios' graphic novel (still unreleased) and stars Tom Cruise, easily topped the weekend box office with an estimated $38.2 million, providing Cruise with his best opening ever  (not adjusted for inflation) outside of the Mission Impossible franchise and the remake of War of the Worlds.  The $120 million post-apocalyptic sci-fi epic was directed by Joseph Kosinski (Tron: Legacy), who also penned the comic book.  Oblivion’s domestic opening was the third best ever in April for a live-action non-sequel.

Last week’s winner, the Jackie Robinson biopic 42, held up well dropping just 34% as it earned $18 million.  The strong showing of the top two films was not enough to keep the box office from slipping 19% from the same weekend last year when Steve Harvey’s romcom Think Like a Man debuted with $33.6 million.

As is typical with science fiction films, males made up 57% of the audience for Oblivion and 74% of the crowd was over 25.  323 fanboy favorite IMAX theaters accounted for $5.5 million in ticket sales and helped the film earn a solid $10,085 per venue average.  Other than the "PG-13" film’s inability to draw in younger viewers, the only bad sign for Oblivion was the fact that opening weekend audiences gave the film a mediocre "B-" CinemaScore, which could signal a significant drop-off next weekend.

Oblivion opened overseas last week and earned an additional $33.7 million this weekend, a decline of just 42%. So far the film has brought in $112 million outside of North America, which puts its worldwide total just north of $150 million, and the film is yet to debut in some choice international territories such as China and Japan.  Oblivion is just the first of 2013’s bumper crop of post-apocalyptic epics with the Will Smith vehicle After Earth in May, World War Z with Brad Pitt in June along with an “end-of-times” comedy This Is the End with Seth Rogen, and Elysium with Matt Damon debuting in August.

The socially conscious biopic 42 has now earned $54.1 million and appears likely to cross the $100 million mark thanks to its "A+" CinemaScore, which so far has translated into a very strong hold.  Meanwhile Dreamworks’ animated feature The Croods dropped just 28% in its fifth weekend, earning an estimated $9.5 million as it pushed its domestic total past the $150 million mark.  As it often the case with CGI features, The Croods is doing even better overseas, where it has earned $274.5 million, bringing its worldwide total to $429.4 million.

The horror spoof Scary Movie 5 dropped 55.5% in its second weekend, which is actually a slightly better performance than its pitiful 5% positive rating on review aggregator Rotten Tomatoes might suggest.

Paramount’s G.I. Joe: Retaliation dropped just 47% in its fourth week in theaters.  Buoyed by a $33 million debut in China, the Hasbro-based movie has now passed the $300 million mark worldwide, which should mean that the $130 million film is now in the black.

The indie crime feature, The Place Beyond the Pines added a thousand theaters, bringing its total to over 1500 as it moved up from number10 last week to the sixth spot.  But the movie’s per-theater average dropped to $3,078, which indicates that its mainstream appeal may be somewhat limited.

The action movie Olympus Has Fallen dropped just 37.4% in its fifth frame as it added $4.5 million and brought its domestic total to $88 million.  Still with just $5 million in overseas sales this $70 million film still has a ways to go before it becomes profitable.  That is definitely not the case for the Evil Dead remake, which fell 57% in its third weekend as it brought its domestic total to $48.5 million versus a cost of just $17 million, nor for Jurassic Park 3-D, which has now earned $38.5 million in North America against a conversion cost of just $10 million.

After seven weeks Sam Raimi’s Oz: The Great and Powerful remained in the top ten as it brought is domestic total to 223.7 million, the best so far for any film released in 2013.

Check back next week to see if the bodybuilding crime saga Pain and Gain starring Dwayne "The Rock" Johnson and Donnie Wahlberg or the ensemble comedy The Big Wedding will be able to unseat Oblivion.