Justice League Hero Dice: Batman is a cooperative game. Each set enables you to play one hero from the Justice League. Each set has material for one player however with multiple sets multiple players can play, with a set for each player (and 2 or more can play Batman, or each a different character).
The aim of the game is to protect your hometown. The villians are attacking Gotham City, Metropolis or another city. Try to push them back. Get bonuspoints for good teamwork. After the attack you can count your points and lick your wounds.
Justice League: Hero Dice is NOT a collectible game, but each different set gives you new and different options.
Don't just take our word for it! Check out this review of Justice League Hero Dice: Batman.