WARNING: SPOILERS...
Saw it Saturday. Impressive CGI work, but otherwise an incredibly poorly written movie with plot holes you could drive an An-225 through (which they did, several times). The writers were just plain lazy, putting cliche after cliche in it, re-running the same escapes over and over: Plane begins moving as ground behind and underneath begins to crumble; plane races down the runway, the ground beneath caving in a hair's breath behind; the aircraft, still slightly below flying speed, carooms into a giant chasm that has opened suddenly, taking the end of the runway with it; plane struggles to pull out as it hurdles downward to the on-rushing wall of the fizzure, suddenly sooming up like a freight elevator at the last second, barely missing (or barely clipping) a collapsing structure (once a skyscraper, once a hill in Yellowstone, and once the Eiffel Tower replica in Vegas); occupants calmly discuss their next move as 100's of millions perish below them...
The entire movie was filled with implausible moments and circumstances, such as cell phones still working from one side of the world to another, after cataclysmic disasters have reduced most large cities to premordial wastelands, or normal evening traffic in D.C. after California has slide into the Pacific and the Yellowstone caldera has detonated like an H-bomb (cool visual effect, I have to admit) and coated everything west of the Mississippi in a pyroclastic cloud of ash, or the Earths tectonic plates moving 1500 miles in 5 or 6 hours (and not completely destroying all life on the planet). The last was done simply to try to explain how the An-225 was able to fly non-stop from Las Vegas to Mt. Everest without refueling.
The one that absolutely killed it for me was when the American ark is spinning slowly towards a collision with the face of Mt. Everast ("We'll never survive the collision!"...though it has already managed to survive being hit by a 1500-ft high tidal wave, colliding with one of the other arks, and hitting a submerged mountain top). One of the ark's large outer access doors has jammed open due to our hero and his family's semi-successful attempt to sneak onto the ark. All they need to do is start the ship's engines and stear away from their doom, but when ordered to do so by the stereotypically self-serving white-male presidential Chief of Staff (the also stereotypically heroic black President has elected to stay behind at the White House, which is crushed by the fictious USS JFK aircraft carrier), the Captain of the American ark says, "We can't start the engines until the door is sealed!

Can anyone say, "Lowest bidder"? Want to make any jokes about "Made in China"? Can anyone think of one good reason why the engines of a ship would be designed to not function if ANY of the ship's numerous exterior access points were not watertight. Oh, and no, the arks were not submersible and neither was the ajar hatch below the waterline. The CoS than demands to know where the "override" is to start the engines in the event that the hatch isn't sealed and they still want to be able to move and stear the ship; "There isn't one" replies an extra in uniform. The whole point seems to be to require that John Cussak's charactor to face nearly certain death ("nearly" is the key word) by diving back under water in the flooded hydrolics bay controlling the door (where there seem to be no hydrolics, only emmence gears that chew up several people, but are relentlessly jammed by a length of pneumatic hose) and free the door mechanism. As if that didn't completely destroy any semblance of reality, the very last scene is where, 27 days later after the air has cleared and the seas have calmed, they open ALL the exterior doors and hatches to allow people to go out on deck and breathe fresh air...and the engines DON'T suddenly stop!

Bottom line, the destruction quickly becomes numbing, the escapes to forumula, circumstances continually implausible in the extreme, and the plot clumsy. Don't bother unless you're just into admiring skilled CGI (you can leave about half way through, as there's nothing particularly impressive after that). Rent it from Netflix or Redbox, but don't bother buying it.