Early in the game, everything goes to pot. Kate has to scramble as more and more water floods in. There might be story spoilers here. As seen on YouTube.
This trailer doesn't give a good sense of what it's like to actually play Hydrophobia. However, it does provide a good look at some of the game's techy equipment.
Kate's weapon in the game is an "LP4", which can be outfitted with various types of ammo.
Here is a teaser look at the game's underwater combat.
There is a fair amount of cover used in combat.
Here are the terrorists that have taken over the ship. Well, some of them. They may not look like it, but they love economist Thomas Malthus.
Much of the action either takes place in corridors like this or in large rooms.
This is a look at a large room. Spacious!
Combat is often less about shooting and more about shooting things, causing them to blow up or electrocute bad guys.