Continuity mistake: When the guy and the girl (the stars of the movie) are jumping out of the big boat, you can clearly see that when they land in the water they are going to fall off and they cut it so that it looks like they landed great.
Continuity mistake: When they have first transferred to the cruise liner, one guy is using a welder on something. In one scene the welder is lit, and in the next one it is not.
Continuity mistake: When the woman is "sucked" into the floor of the bathroom, at one point she accidentally pulls a faucet from a sink next to her, causing water to begin spraying upwards and raining down. Problem is, less than two seconds later, she's already completely soaked and we see a closeup shot of her kicking her feet, and there's already a large volume of water on the floor. Far too much water for how short a period of time it's been coming out of the faucet.