Scientist discover that the ocean has a basement. While exploring this newfound area, they (being idiots) accidentally release two megalodon sharks. One is big as fuck and the other one is really big as fuck. Unfortunately, these two sharks don't bring along any good writers, because THE MEG, while it sounds exciting, is completely soulless. After the sharks escape, instead of just wandering off into the ocean to never be seen again, they attack the underwater research facility where the scientist hang out. That's not as exciting as it sounds, but it does give the scientists and friends reason to chase the sharks around for the rest of the movie.
I love killer animal movies. Successful ones have strong character development capped off by an awesome second half full of the monster(s) wrecking shit non-stop. (Or...the movie is just so bad and/or insane that you can't help but enjoy it.) None of that happens in THE MEG. Right from the start, the characters are all very bland and forgettable. The shark itself looks cool, but it never goes crazy and starts ripping people apart. The majority of the action is simply the sharks eating other animals with only the occasional human getting nibbled offscreen. It's weak as hell.
That said, I was mildly entertained. The movie itself looks nice and the pace moves along quickly enough to keep you from getting too bored, but with zero point zero percent chance of something wild or unexpecting happening, my mind did start to drift. Like...I still don't understand why there hasn't been a killer animal movie where the critters attack a nudist colony! Preferably it will be set in the 1980's and the critters main attack happens during the final round of an all-nude breakdancing contest.
Low body count, zero nudity, zero tension, boring action scenes, unrealistic dialogue, an annoying little kid that knows everything (vomit!), Jason Statham as "Jason Statham versus a giant shark", Rainn Wilson being 100% forgettable, Robert Taylor's acting talent wasted, absolutely zero concern for decompression, disappointing ending.
Not the worst giant killer animal movie ever (and I'm 100% positive that I'll end up watching the sequels), but for a sanitized, inoffensive time-waster it's not too bad.
[Update 08/25/2023: Saw Meg 2 or whatever it's called in the theater and it was fun. I'll post a new review for it once I get a blu-ray to take screenshots from.]