We just saw this movie (at home, not on the ship), and I must agree that it has little to offer an adult audience. Little plot, characters doesn't mesh with the previous two movies (they're still letting the previous movies' bad guys work in the OSS? I don't think so) . . . I didn't enjoy it much.
On the other hand, my two daughters (ages 6 and 9) LOVED it and are already begging me to buy it when the DVD comes out! They were intrigued with the 3D effects, which were entirely new to them. The older daughter is motivated to learn to DRAW in 3D, and we're going to buy a book that was recommended by my elementary school art teach friend.
Which brings me to a new question . . . suppose there's a movie that my children want to see (or repeat) during the cruise. Is it acceptable to take them to the theater, see that they have a seat, then return just before the movie ends to pick them up as they exit the theater? These kids are 6 and 9, and they know how to behave in a theater. Is this appropriate on the ship?