Using Nauto98001's strategy, on my FIRST TRY in realistic mode (and the only time played in realistic mode for me) I successfully destroyed humanity (YAY!) in just over 68 days, for the easy, hard, and "impossible" badges all at once. Plus this and plus the post with the strat if you don't mind
Upgrades that would be cool are rearview mirrors, drafting for more boost, all-terrain tires, and a way to see upcoming turns more effectively (like the suggested minimap or simply a wider view). Thanks.
This got me 1st on every race: Max out engine and handling, leaving the rest for boost. You will only need to worry about reaction time for turns. Use the boost when it gets half full or more to ensure a 1st place.
If you don't get first because you fly off the road and wreck on the guardrail, use your boost and go off-road before that turn, so it's impossible to hit the guardrails.
Make sure not to get stuck behind other cars; you won't gain speed and if you're using a boost it will be wasted.
Plus if this helped.
To get the achieve on for "defense" on expert, fill the center with mortars and run around dropping barrels around the map wherever zombies are. The mortars detonate the barrels, the barrels kill everything, saving the mortar ammo for more rounds. every time you have the chance, plant more mortars. if you run out of barrels, use the minigun to clear a spot. Watch out for the devils (red ones) when they're firing their columns of flame and you even won't get scratched. + if this is helpful
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