Plague Inc: Evolved [official site] is, at heart, ye olde Flash game Pandemic. Players design and evolve an infection to spread across humanity and, ultimately, wipe out all 7.4 billion of us blights upon the face of the Earth. Around that, though, Plague Inc adds all sorts of new and exciting ways to kill us vermin, mod support, competitive multiplayer and, now, co-op too. After two years in Early Access, Plague Inc: Evolved has reached version 1.0 and properly launched. Possibly ejected as a virulent sneeze on a crowded train. The game slrrrrpps down your cheek. You politely clear your threat and pretend not to notice, muttering about the Evening Standard's Sudoku.
The launch update has added co-op multiplayer where two folks create their own infections, working together to kill us all - though humanity strikes back harder against these double-pronged assaults. It also adds an AI for the regular multiplayer mode, which puts one player in charge of humanity's attempts to defeat the infection.
Though it's now out of Early Access, developers Ndemic Creations (who didn't make Pandemic, to be clear) are still planning more updates. "New modes, cheats, scenarios and official disease types are in development," they say.
Plague Inc: Evolved is £10.79 on Steam right now. Here's an old trailer: