This game gets extremely tough, very quickly, so the first thing to look for once things get hairy is the structural integrity of your Freeblade. Your structural integrity drops as you play more rounds, it drops your attack and defense, and it needs to be repaired in order to be in good shape again. The icon in the top left corner of the screen will go from green to yellow to orange to red as the structural integrity drops. Tap it and you can either spend gold, watch a video to repair it, or see how much time is left before it's done.