Plague Inc. Black Death Scenario Mega-Brutal(3 Biohazard) Guide & Walkthrough

The Black Death scenario in Plague Inc. simulates the spread of one the deadliest plagues that took the lives of millions of people. There is a link at the scenario description that leads you to a wiki page that describes what the black death is, and how horrible it truly was. In this scenario, an unlucky person is once again infected by this bacteria(?) in today's world where there are tons of medicine that could quickly counter your plague.

I can't take full credit for the guide I'm about to post since I've only made a few changes to a guide made by an anonymous wikia contributer(link here).

The main key to this strategy are symptoms. We'll evolve every symptom possible and spread the plague through transmissions and resistances. In order to get a 3 biohazard score in mega-brutal, you'll have to finish within about 350-360 days with a cure completion of less than 60%. Obviously this isn't easy to do, I've spent days experimenting on evolution orders just to do this, lucky enough I've found a guy who has made a guide for brutal difficulty that worked extremely well for mega-brutal, with a few changes of course.

There are several factors that could hinder you from getting those 3 golden biohazards. The first mention should definitely be Genetic Shifts, increase in DNA costs could mess things up so bad. Second, Random events such as Charity events and events that speed up cure progression could also affect your success rate. We need the cure progression to be below 60% and finish at less than 360 days. Lastly, mutations, these could either make or break your game. Mutate a lethal symptom to early and you'll see countries quickly closing their point-of-entries and speeding up the cure completion.

Now let's start. First off, the gene setup:

• Catalytic Switch
• Suppression
• Sympto-Stasis
• Genetic Mimic
• Extremophile

TIP: Evolve as soon as you can. Once you get the DNA, evolve immediately. This is because we want to avoid Genetic Shifts from increasing DNA costs. Also, let the plague mutate freely, this will save you some much needed DNA points.

1.) Start in China

2.) Evolve the following symptoms, transmissions, and abilities in this order:

• Cysts
• Flea 2
• Skin Lesions
• Rodent 1

3.) At this point, evolve the ability Pneumonic Plague, then evolve as follows:

• Coughing
• Sneezing
• Drug Resistance
• Livestock 1
• Bird 1
• Cold Resistance 1
• Water 1

4.) Time to evolve Septemic Plague, then start evolving these in this order:

• Abscesses
• Nausea
• Vomiting
• Pulmonary Oedema
• Haemoptysis
• Heat Resistance 1
• Drug Resistance 2
• Air 1

5.) At this point, it would be best to slow down the cure. So evolve Genetic Re-Shuffle and Drug Resistance 3. Continue evolving:

• Cold Resistance 2
• Heat Resistance 2
• Environmental Hardening
• Blood 1

6.) We'll be focusing on symptoms at this point. 

• Diarrhoea
• Dysentery
• Hypotension
• Hemorrhagic Shock
• Total Organ Failure
• Hyper Sensitivity
• Inflammation
• Seizures
• Paralysis
• Evolve every remaining symptom. Prioritize lethal ones first.

7.) DNA in this point of the game is best used to evolve Genetic Re-Shuffles.

That's all there is to it. I don't guarantee a 100% success rate with this guide, it's at 50% at most I guess. Out of the 4 games I played, 2 of them successfully finished with a 3 biohazard score. Again, you'll need to finish within 360 days and have the cure completion below 60% to attain a 3 biohazard score. 

If you're like me and failed a lot of times trying to get a 3 biohazard score in this scenario, trying a strategy like this one for 5 times or more shouldn't be too much. Getting a 3 biohazard score in this scenario is not easy.

POSTED GUIDE BY TIM:

Chose to post this guide since it has been working for a number of people. Thanks to Tim for sharing his guide at the comments section!

Finally got 3 Bios--cure completion was 61% but I finished in 346 days for a score of 65237.

My gene setup:

ATP Boost (quick start)
Aquacyte (for the islands)
Sympto-Stasis
Genetic Mimic
Urbophile (for a quick start in China)

Note: If you get the awareness day early on, I'd just restart. You'll never get a low enough cure %. Even so, it takes a lot of luck to avoid a fast cure and get all the islands.

1.) Evolve Skin Lesions, then start in China
2.) Evolve Cysts, Hyper Sensitivity, Flea 2, Rash, Sweating, Rodent 1, Livestock 1, and then Bird 1
3.) Switch to Abilities. Evolve Cold 1, Heat 1, Drug 1, Cold 2, Heat 2, and Drug 2.
4.) Evolve Genetic Hardening 1 once the cure starts to take off (less than a year left)
5.) Evolve Pneumonic Plague and the following symptoms: Coughing, Sneezing, Pneumonia, Haemoptysis, Immune Suppression, and Paralysis
6.) Evolve Water 1 and 2 (this is where you pray for quick island infection)
7.) Evolve Environmental Hardening
8.) Evolve Septicemic Plague and the following symptoms: Abscesses, Nausea, Vomiting, Diarrhea
9.) Evolve Blood 1
10.) Reduce your cure progress with Genetic Re-Shuffle 1 and Drug 3 (I put these off for later because they have more impact on cure %)

From here on out just evolve TOF and every other lethal symptom, saving enough DNA for Genetic Re-Shuffle 2. If necessary, de-evolve some of your transmissions or symptoms for extra DNA at the very end.

This isn't a perfect strategy but it's the only one that worked for me.