If you're like me, you may have dug around a bit for an easy way to clean up the remaining kills that you need after you've done the 5 skulls for every level on war mage difficulty, and completed nightmare mode. Not able to find anything myself, I came up with this method to achieve the 30 thousand kills as quickly as possible. I'm going to assume that you have completed the game at least once and have every weapon/trap at your disposal. If not, you really don't need this guide yet. Let's begin!

Go ahead and start off by selecting the, "Chokepoint" level.
Once you load in, open up your weavers and buy these skills.
Now select these weapons and traps. Note that you WILL have disposable income, so if you wish to bring anything else along with you, go ahead.
Place your traps like this and begin the wave.

At this point, you want to stand here and use your flame bracer to kill the orcs as they funnel through your barricades.

As you can see, with this start you have just enough money every round to add one more row to your traps.
Occasionally, an ogre will come burling through between waves. Freeze him with your ice amulet and headshot him with the crossbow to quickly dispose of him.
Around wave 6, you should have your funnel fully completed. At this point, feel free to spend the rest of your money on anything else. I prefer to just finish maxing out the weaver skill tree, but you can place damage traps if you wish.

Here is my ending stats. A pretty short amount of time for a large amount of kills, I'd say. Good luck!