I watched this movie because it's "free" on Prime and I was in the mood for a mindless monster movie. Unfortunately it began at my lowest level of expectation and, excepting a few moments when it managed to reach the surface and thrash around a little, sank like a stone into an abyss of cliches, bad dialogue, stock characters, CGI and pro-Chinese propaganda. The movie even ends with a picture of the Communist flag fluttering in the breeze. I'm hardly one to bring politics into entertainment on a whim, but the soft-soaping of the appalling Chinese regime is so blatant in this movie as to actually be insulting.
I won't waste time on this trash by breaking it down into particulate matter. Basically, if you've seen "Deepstar Six," "Leviathan," "Deep Blue Sea," or the 2010 version of "Pirhana" you've already seen this flick. Almost absurdly diverse group of deep sea explorers funded by morally ambiguous billionare discovers thriving ecosystem in the ocean's sub-basement near the Chinese coast. Accidentally releases 75-foot killer shark Megalodon into our ocean. Stranded crew of mini-sub requires troubled, haunted loner-hero who left rescue profession under a cloud to come out of retirement and save them. Loner-hero must redeem himself while saving ex-wife, pursuing new love-interest, and battling mega-shark. Mega-shark eats various lesser characters and then heads for the beach to slaughter Chinese bathers...unless hero and surviving lesser characters can stop it! Etc and so on. Do I object to the recycled plot? No. It's a monster movie. I object to the fact they spent $140 million on a movie whose script is so sodden with cliches and limp stock characters (most of whom are suspiciously good-looking) it's like a bowl of week-old cereal. I object to the waste of Jason Statham, who is a better actor than he ever gets a chance (or gives himself a chance) to play, and especially Rainn Wilson, who seems to be under-exerting himself out of sheer embarrassment over the script. But I mostly obect to the crass and repeated attempts to present China in the most flattering possible light when we all know it's a horrific tyranny about a half-step better than North Korea. Hollywood's pandering toward this gulag-state is so utterly without scruple or dignity it makes my colon clinch.
I won't say there are no worthwhile moments in this all-CGI, all-the-time monster flick, but they come at long intervals and not nearly often enough to save this trash from the garbage can where it belongs. This film is living proof that the bigger the budget, the less effort is made to actually produce a decent movie. It's all about the first weekend cash-grab, baby! If you want a mindless, silly horror movie about flesh-eating fish who rise from an undesea tomb to eat hapless bathers, watch 2010's gory, T & A-laden "Pirhana," which is at least funny and refuses to take itself seriously.