Game is GREAT, but there is an easy way to win.
SPOILERS!
All you really need to do is train the first page of guys up to maximum level and fight until you have 5 Turrangamassa levels.
After this you just simply go to the last page of cards and choose "Stone Catapult".
Train the "Stone Catapult" up to max level.
Use the "Stone Catapult" to get to level 9 Turangamassa and then choose the "Arrow Catapult".
Train the "Arrow Catapult" up very high and then start battling again. Get to Turrangamasa level 13.
Choose the Missle Silo.
Win the game.
Congrats.