Marvel Battleworld: Is It More Than Just a Mystery Box Gimmick?

About Marvel Battleworld, from BoardGameGeek:

GAME SYSTEM This entry is to allow for discussion/rating of the game system as a whole. It is not for a specific product or release. Versions will appear on the individual item pages. Pick your favorite Hero, rescue your friends, and win battles to defeat Thanos! Marvel Battleworld is a revolutionary cooperative, expandable, collectible adventure game featuring dozens of characters from all over the Marvel Universe! Players get to crack open the mysterious Thanostones during the course of play to reveal mystery characters inside. Choose your favorite hero, and use their unique special abilities. Roll to attack and win three battles to achieve victory! -description from the publisher