Continuity mistake: In the beginning when Mariner goes diving off his boat for sunken treasure, he fills a timer with a handful of small stones which steadily drop to bring up the diving equipment when exhausted. After the camera shows some scenes to imply time going by, you can clearly see the amount of stones fallen is equal to about ten handfuls of stones.
Continuity mistake: After the mariner escapes the atoll and begins turning the gunboat towards the deacon, we see the firing path pass the end of the atoll wall. A couple shots later, it shows four smokers on jet skis getting shot as they exit the main gate, which is in the center of the wall facing the attack and had already been passed by the firing path. (00:38:00)
Continuity mistake: When Mariner is knocked into the mud pit while in the cage we see that it does indeed sink. However as the woman and the girl are crossing the bridge to get to the windmill, the camera cuts to Mariner in the cage. The cage has sunk so that he only has room for his head and shoulders. Then as the woman and girl run past him there is another shot in which the cage is now further out of the mud and Mariner has room for the majority of his upper body.
Continuity mistake: After the Mariner rescued Enola, the Deacon and his goons collide. As the fireball of their collision comes up, their wakes are still visible. A second later, the fireball is still growing but the wakes have totally subsided. Not possible given the explosion is only several seconds old.
Continuity mistake: Near the end one of the balloon's ropes is shot, causing the girl to fall in the water. Yet, seconds later as they float off all 6 ropes are holding the basket up, uncut.
Continuity mistake: When the Mariner escapes the Smokers for the first time, we get a wide shot of him at the helm. During the first shot, the boom is nearly straight over the boat and the outhaul is tensioned. In the shot afterwards, the boom is much further outward, and the outhaul now has lots of slack.