@pierre90: You can get well under 3.5 minutes. Don't build anything except enough collectors to connect to the outer two totems. Then move OC so its connected directly to both the network and middle totem (you'll have to move it into the creeper). I cleared it in 1:34.
 "Creeper World: Evermore"){kind=icon}
 "Flatland: Fallen Angle"){kind=icon}