Its a great game! Havent spent a dime for better upgrades; like usually do... The key is to keep playing until you unlock super upgrade on towers (starting with arrow tower). Know where to place them (in path of flyers) and let them gems roll in. Keep upgrading. Ive got perfect on 1st 5 missions on normal and hard. So it is possible!!! Its a good game. On a free day, i could spend a couple hours playing.
iPhone 5c !!! about Goblin Defenders: Steel'n'Wood