Defense...
	Gold or silver trophy...
	Unlimited lives...

Upgrade your defenders to their full potential. Focus on spending your training points on defenders that have long range attacks as well as those who can do multiple hits at the same time.

To increase the chance to earn a gold or silver trophy, reach the end of the level without the princess getting hit. The more hits the princess takes, the lower the trophy will be.

Normally if you run out of lives you must wait for them to be restored over time. Advance the time on your device by 45 minutes per life to be restored to instantly replenish them. Then, set the time back to its correct value.