@thekato: Actually you find a note that says where the street is to find it, then they say it grew too big and that it's too late. You DID find the virus. Watch the end and yo will see that you did indeed find the virus.
Wow, why does everyone say you can just go to a new tab? Try a harder mode and you will see that your army will be wiped clean for just throwing them forward.
@VMUTFN: The retreat and march buttons do work. They are for specific units. You can click 1 type of unit or multiple and click march to send the group forward and retreat to bring them back.
To beat the stealth goblin(s), have mana fully upgraded, and have the skill "Stop" fully upgraded. You can't knock the stealth goblins back in this game. You have to run passed them by stopping the enemy movement. Click + so everyone sees this.
You dont change the difficulty level, you select a level that you have beaten, and you get the option to play it on hard, beat that and you get the epic option.
 "Zombies Took My Daughter!"){kind=icon}
 "You Have To Defecate Upon King Bhumibol"){kind=icon}
 "You Only Live Once"){kind=icon}
 "Classic Pong"){kind=icon}
 "Epic War 4"){kind=icon}
 "The Next Floor"){kind=icon}