I was fascinated by the original Cocoon movie which had a real novel theme and succeeded in making most of us think of the value of old age, the struggles, aspirations and what would happen "if only they could". It was touchy, endearing and with real after thoughts generated out of the theme of aging.
But the return is nothing novel and nothing like the first. It is embarrassing at times. Jack is back with Kitty! Oh ma! We may have excused the innocence of the initial encounter but what is happening in this movie was from clumsy to simply unsophisticated. The pregnancy topic is a mediocre addition, there is an under developed story between the Grandpa and the grandson and overall, nothing really new happening we have not seen in or extrapolated from the first movie. The original cast of "oldies" stays more or less within character and if it was not for hem and actors like Jessica Tandy (Driving Miss Daisy, Fried Green Tomatoes, ...) I would have given an even worst grading.
In short, the magic was gone and it would have been best not to make a sequel.