Tower Defenders puts your strategic skills to the test as you fend off relentless waves of undead Vikings. Use resources to place and upgrade towers strategically. Gather rewards to boost your powers and prepare for upcoming battles. After every pair of levels, enhance abilities with special cards.Select and elevate towers using earned resources. Gain coins and gems by overcoming enemies for additional upgrades. Every two levels, pick from three cards to enhance strategies. Balance attack with defense. Hint: Plan for upcoming waves when positioning towers.