Gold Coins were a common currency in unlimited tower defense games to buy items and equipment in the game. Here are some ways to obtain gold coins: 1. Complete the game mission: Complete the mission to obtain a certain amount of gold coins as a reward. The rewards for different missions are different. 2. Defeat the enemy: Defeating the enemy in the game will reward you with gold coins. The rewards for different levels of enemies are different. 3. Buying items: Items in the game need to be purchased with gold coins, such as defensive towers, missiles, etc. 4. Mission completion rewards: Completing certain missions in the game, such as completing main missions, challenge missions, daily missions, etc., will also receive a certain amount of gold coins as a reward. 5. Arena Battle: Fighting in the Arena can obtain gold coins as rewards. The rewards of different levels of Arena Battle are different. Gold coins were a very important currency in the infinite tower defense game. They could be used to buy items and equipment in the game to increase the combat power of the game.