You can earn more money by completing levels quickly, performing stunts, and defeating zombies. Also, try to upgrade your vehicle and weapons to increase efficiency and maximize your earnings.

Upgrades include improving your vehicle's speed, durability, and weapons. You can also enhance your fuel capacity, allowing for longer journeys and more zombie kills, which gives you a better chance to earn more money.

New vehicles can be unlocked by progressing through levels. Completing specific challenges or reaching milestones during gameplay will also grant access to additional cars, each with unique abilities.

To tackle challenging levels, focus on upgrading your vehicle thoroughly before attempting the level. Additionally, plan your route to maximize efficiency and minimize time spent in hazardous areas, ensuring you gather enough resources.

To maximize XP gain, complete as many quests and challenges as possible. Try to achieve high combos by hitting multiple zombies in quick succession. Upgrading your vehicle to increase kill counts will also improve your XP earnings.