Although your goal is to kill the world, it does present some interesting science concepts.
Community Review for Plague Inc.
My Take
There are a lot of people who don't want to use this app because the focus is to create a bacteria/virus that will wipe out the world. However, it's a great hook for a unit on the spread of viruses. Students quickly understand how different factors can impede or help the spread of disease. I would only use it with advanced high school students.
How I Use It
I would use this app as a hook for a high school science class. When teaching communicable diseases, it can be hard to fathom how disease travels around the world. This app would be a way to provide a visual, interactive method to see the different factors that go in to spread. I would only use it for a max of one class period. The app can take multiple days depending on the settings.