For This One, I Played Bio-Weapon On Normal.
I Started In China And Found The Virus Pretty Quickly In The USA And Mexico.
After You Find It, Try To Quarentine Ports First, Try To Spare As Many Island Countries As You Can And Hope You Can Keep it On One Side Of The Globe.
Research The Bioweapon Response "Announce Doomsday Threat To World" For A Bunch Of Free Authority. Also Get The "People Will Comply With Quarantines" Upgrades x3.
Then Try To Stave Off Whatever Continent You Can Until Your Authority Drops To Near 10-20.
At This Point Buy The "Censorship" Upgrade, Your Authority Wont Drop At All For Like A Month, By Then Hopefully The World Population Is Much, Much Lower.
Once You See Your Authority Start To Move Again Buy The "Fake News" Upgrade, Which Does The Same Thing.
If Your Quarantines Held, Hopefully Most Infected Countries Will Have Died Off By The Time Fake News Gets Debunked.
The Virus Killed All Its Hosts By The Time Fake News Wore Off For Me, I Dropped To Zero Authority Right Before The Game Ended.
Pro Tips:
While Fake News And Censorship Are Active You Can Do Things That Would Normally Lower Your Authority With No Consequences, Like The "We Can't Save Every Country" Or The "Extreme Measures" Upgrades.
This Can Be Combined With The "Doomsday Save" Achievement.
Good Luck!
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