Completion Strategy:

In this level, we have the tattooed asian, verse 2 Scourge Spltters.
When playing this level for the first time, the bots seem to be very fast paced, almost like the PerfectSims in Perfect Dark.
This is quickly overcome with the right weapons.
There aren't many good weapons to use in this level, but a few good weapons in particular are the SBP-90 2x.
Well... actually, the SBP-90 2x is the only good weapon...
Just stay away from the useless Sci-Fi Gun or ElectroTool.
Because of the fact that there is no radar, you'll have to guess where they are located.
I like to constantly spin, and try and sight their movements.
Or... if you're a legend, you can judge where they are by the sound of the spawns.

- Lenny

Platinum/Fast Time Strategy:

If you want platinum, you'll have to spawn near any of the 2 SBP-90 2x locations.
I can't explain in great detail where they are located, but with a bit of hopeful knowledge from you, you should be able to understand my explanations.
The first SBP-90 2x is inside the building on the second floor.
There are 2 stairs. Go up the stairs closest to the left.
The second SBP-90 2x is located in the same place as the other rocket launcher was located in Amateur League level, Chastity Chased.
Don't understand? Not a problem.
Looking from the starting place in Challenge. Fight Off The Living Dead, go all the way at the back, and you should clearly see it.

Because that's out of the way, I can now move on to further advice.
The Scourge Splitters are fairly fast, and this can cause several problems.
First of all, you need to be looking around a lot.
Once you make kills, look around, and see where they are, and kill them ASAP.
One weapon that can actually help you in knowing where they are, is the ElectroTool. Sometimes when they are equipped with it, they point it at you non-stop, thus, the electricity beam leads to where they are.
Another problem is that they tend to be glitchy with their movements.
They sometimes either spin round and round in circles in an insane-like manner, or they run towards walls, and get stuck.
This happens a lot, especially when they're inside the buildings.
If you see none of them for a while, you'll have to look for them by checking different places, Those are basically some points you might want to take notice of.
Another thing, is that sometimes, they tend to use the cloak power up.
If they do, they can still be slightly visible, because of the purple gases that levitate their heads.
They also tend to use the shrink power up.
If they do, well... there may be delay in the kills.

Basically like the other levels, look for the enemy, and gun them down as fast as you can.
If you run out of ammo, just get more SBP-90 ammo.
There's 2 SBP-90 2x locations, and 3 single SBP-90 locations.
Platinum shouldn't be too frustrating to obtain.

- Lenny