A very simple strategy: make a deck with only gold mines and fodder units (requiring only gold to play and summon), draw out the deck to maximize gold income, then just swarm the enemy with sheer numbers. Works.
Pretty good game, though I didn't get the ride the lightning badge because there was a slight glitch and for some reason a gun ended up right on top of the back button of the ship upgrade screen, which I couldn't do anything about, so it counted it as a part that wasn't upgraded >.<
 "GeoSketch"){kind=icon}
 "Cardian"){kind=icon}
 "Doodle God"){kind=icon}
 "Stick War"){kind=icon}
 "Protector III"){kind=icon}
 "Mastermind: World Conquerer"){kind=icon}
 "UPGRADE COMPLETE!"){kind=icon}