@Panthalassan: actually, everybody, including BO tracker sites, knew that that wasn't going to happen, with 'X-Men' coming out the very next week, which was, by all accounts, a much more anticipated film, followed immediately by 'Maleficent' the week after that, two films with a much bigger following and fanbase than Godzilla, one of em being a sequel and the other being a retelling of a famous Disney franchise. 'Godzilla' catered to kaiju fans (or whoever wanted to see it), 'X-Men' catered to Marvel fans, and 'Maleficent' catered to Disney fans, the later 2 being much more popular both in the states and abroad.
Bottom line on kaiju films is:unless they're directed by Speilberg or Jackson, they're going to have huge drops, look at 'Cloverfield' which had a 68% 2nd weekend drop, higher than Godzilla's despite it having no competition ('Rambo' and 'Meet the Spatans' don't exactly count as top-notch competition) and 'Godzilla' having X'-Men' to deal with the very next week, so it exceeded expectations by all accounts.
But like I said, the fact that it held up better than 'Cap 2' every weekday after both films' OW until 'DOFP' opened proves it wasn't a poisonous response that caused the drops. Look at 'Hellboy II': solid critical response, and an improvement over the first film's OW numbers, but it fizzled out due to having 'The Dark Knight' come out the following weekend, it had nothing to do with some kind of poisonous response to the film: nothing any number of viewers had to say regarding the film was going to stop people from flocking to see TDK (easily in the top 5 most anticipated films of all time, possibly top 3 even) the very next weekend, same concept with 'DOFP' the week after 'Godzilla' came out.
And again, it bears repeating: it still made more money than all of these films even in spite of all of this. Heck, 'Batman Begins', another series starter, received similar hype, even had a marketing budget of $100 mil, same as Godzilla's, and buzzing critical response to boot, and it made over $100 mil less than this worldwide despite facing significantly lesser competition ('War of the Worlds' and 'Fantastic Four' are not exactly on the level of 'DOFP' and 'Maleficent').
Also, forgot to add 'World War Z' to this laundry list of series openers it beat.