How do you upgrade your fighter and unlock new abilities in City Brawl?

To upgrade your fighter in City Brawl, you need to collect coins and power-ups earned from completing missions and defeating enemies. These resources can be used in the upgrade menu to enhance stats like strength, speed, and health. As you level up, new abilities and special attacks will automatically unlock, giving your fighter more powerful moves to take on tougher opponents and bigger challenges across the city.