There is a scene on the island where prisoners are seen from afar being whipped.
The submarine is attacked by a giant squid. This entire sequence is intense.
Two men fight very brutally with each other and one man is presumed knocked out. Later, a man is shot and blood is shown through his clothes.
Typical action movie violence such as fistfights, a few gunfire scenes. No gory sequences.
Capt Nemo mentions that his wife and son were tortured to death.
Nemo's sub attacks a ship, and an island explodes. It is implied that many were killed.
There is one scene where a man is almost attacked by a shark. The shark is shot and its blood is seen in the water.