This was a toughy, but similar in strategy to the Survival version where you have to space out turrets to catch invisible toys -although you'll see I failed at that at certain points. I tried this level with Hollowpoint as well but couldn't figure out how to deal with the boss (but it was easier to get to the boss level with 20/20 core health) -perhaps adding a summon card would work but I wonder if it would be enough HP to tank the boss... Anyways, very difficult level solo on Nightmare, I tried to partly replicate the strategy for Survival by spacing out the turrets and focusing on where at least two waves will run past. However, as you'll see in the video, this isn't a perfect run. Another key to the level is Chum's Chompers, they have a hard time locking in on the boss but can kite the boss away from the core if toys come close. I think with some tinkering with this setup it is possible to get a perfect run.