Infestation is probably the easiest overall challenge in
Starcraft 2 for earning the gold medal.
Infestation requires little micro and the time is very generous, so with the strategy here you should be able to
get the gold medal on your first time through.
The key to this challenge is to use the Neural Parasite ability. Fungal Growth is a waste of energy here, though
the way the Marines are clumped up makes using this ability tempting. Resist the temptation and use Neural Parasite
on the appropriate units and this mission is a breeze.
Infestation Gold Medal Video Walkthrough
If you can watch the video below, it most easily demonstrates how to beat Infestation while earning the gold
medal. There are multiple methods for getting the gold but this strategy is a solid way to do it.
Step by Step Infestation Strategy
You can get almost all the required kills you need just by using Neural Parasite (mind control) a few times.
Before the mission starts, take a look at the map. You will notice there are 6 Siege Tanks. I recommend burrowing
an Infestor and sending it to directly to each Siege Tank. You will also see 3 Colossi on the map. Burrow your
remaining 3 Roaches and send one to each Colossus.
Once your Infestors are in position, unburrow them one at a tmie and mind control each of the Siege Tanks. The
Siege Tanks alone will then kill off most of the units you need for the Gold medal.
To get the rest of the kills you need, use your remaining 3 Infestors to use Neural Parasite on the Colossi.
There is a few caveats:
For the first Colossus (to the northeast), you have to kill the three marines guarding it. Three Roaches
burrowed up here will do the job just fine.
For the second Colossus (northwest), you need to make sure you mind control the nearby Siege Tank first, and
make sure the Siege Tank does not kill the Colossus before you use Neural Parasite.
For the final Colossus, it is directly next to a Siege Tank. You will want to pop up with both Infestors so you
can grab the Colossus and the Siege Tank simultaneously so they do not kill each other or kill your Infestors.
These mind-controlled units will easily clear most of the map. If you want to try to get a high score beyond the
Gold Medal, be sure to kill off the mind controlled units with your Roaches after they have done most of their
work. This frees up the Infestors to use Infested Terrans on the remaining buildings.