Was able to pull a version of this off again; I stopped short of fully exterminating Gloomy’s cards, since it was getting tedious to avoid killing him, but I did manage to fully clear the Wasteland, including the Mongolian Death Worm. That was very hard; depending on whether one or two Skunk Apes are in play, you either need to deal 6 or 7 damage, no less or more, during the interval between the Worm entering play and the final Ape devouring it. L’Embuscade plus Coute Que Coute and possibly another+1 are the best way to do this, but I had spent them early on other things. In the end, with Coute and Galvanize up, I had to have my Dramatic Cliffhanger fire Lance-Flammes for 4 first, to avoid triggering the destruction clause, and then play The Usual Solution to hit something else for 4, destroy my own Coute, and then hit the Worm for exactly 2, allowing the Ape to drag it off.
While Gloomy died mercifully quick after that, I did have time to eat all five Zombies, two Relics (never saw the Drum), three or four Cultists, and all of the pins except maybe one. With Legacy and Dr Medico in the party, I literally couldn’t get anyone but the Doc to take any damage; whenever Universal Donor was triggered, the other two were at full HP (though UD still forced me to pick a target every time, which got annoying). Though Medico had to bounce back from single digits, the game ended with all heroes at full HP. The Final Wasteland is safe again… for now…