Well, I finally watched the movie, and I have to say that it was 10 times better than the first.
WARNING: THIS REVIEW
CONTAINS SPOILERS!After watching the first sixteen minues of the movie, I already had a feeling that it would be better than the first by a long shot.
I'm providing screenshots of bother creatures to show how fake the shark looks compared to in the first movie.

I have to admit, this looks like the supergator from Dinocroc vs. Supergator.

The begin was rather surprising to me, the croc was able to fit in a cave that a semi could barely fit it, and it was 1500 feet long and 45 feet wide.
Somehow the shark from the first movie was still alive too, and somehow a girl got a shark tooth in her waste, but she wasn't anywhere near the shark.
When the croc walked across a roof of a building, it didn't even crack it.
The shark was also able to take .50 caliber BMGs fired from a machine gun, that isn't possible it real life at all. Even a megalodon can't take that.
They even fired at the croc with the same kind of guns, and rounds from a tank, didn't leave a scratch.
Then here's what I don't get: they were shooting missiles at the shark after it swallwed a nuclear sub. Other than blowing up Hawaii, what did they expect to accomplish by doing that?
The croc hit a helicopter, it crashed and blew up, but it happened again later, it just crashed, and was able to fly later?
One of the main characters was firing a machine gun, but you never saw the flash or anything and it sounded like a pistol firing.
The main character fired a sawn off shotgun (2 rounds only) at the croc and shark, he fired about three shots, but what did he expect to accomplish with a sawn off shotgun and revolver?
The shark also swallowed a nuclear sub, how stupid could the shark get? It also caught a missile fired from the sub in its jaws, and tried to swallow it!
I'm just going to skip ahead to the ending, they try parylyzing the croc with electricity and trying to trap the two in small streams meant for small boats, which they bust out of.
Then two of the three last people end up at one of the Hawaiian islands, and they end up triggering an underwater volcano to blow up killing the croc and shark, then they end up flying away in helicopter before it does.
You see the two creatures get sucked into the lava, but, for some reason, I have a feeling that the shark at least will be back if they make a third movie. Then they'll probably do something like Mega Shark vs. Mega Spider or Mega Shark vs. Godzilla or some other crossover.
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Anyway, I'd say it was worth watching, more than the first anyway, but that's just my opinion.