In Tower Defenders, you have to defend yourself against waves of zombie Vikings.
Start by putting and improving your defense towers in a smart way using the resources you have access to. When you beat enemies, you get coins and gems that you can use to buy more upgrades. Every two levels, three cards from a deck of 18 magic cards are given to the player. Pick the card that fits your plan the best to make your shields or attacks stronger.
Don't forget how powerful planning ahead can be. Prepare for where to put your towers and how to improve them. Balance is important; don't just focus on offense or defense; try to do both well. Carefully think about the unique skills that each magic card has and pick the ones that work best with your general plan.
Have fun and good luck!