I strongly recomend Gamer to clear the market so the items can get lowered in price, and the acivments make them give gems or money that would be cool.
Walkthrough... in relaxed use the drugresistant parasite (the oe in middle) then upgrade all of the resistance, then the symtoms DO NOT buy the transmision cuz itll spread and itll be really weak
after you max out drug resistance and syntopms you upgrade the Transmisions and in 2 mins itll be all over i think