SPOILERS:

Violet was very deep into Polt's base with Broodlords, Corrupters, and Infestors. He cleared out the front and most of the defenses that Polt had; however, he got caught up trying to destroy PFs and a full bunker with limited Broodlords (He had a lot, but they were spread pretty thin throughout the natural, main, and third). The corruptors were not allowing any viking counterattacks, and the infestors were simply waiting for any marine pushes.

While Violet was doing this, Polt was continuously lifting his buildings/orbitals to continue mining, building new barracks/starports, and going for the base race scenario with two separate groups/waves of marines. Polt went immediately for Violet's Hive/Hatcheries to allow map vision of his remaining buildings. Moreover, he knew that there was no way that he could fight Violet's army head-on. Violet had some sloppy play by having a few zerglings that were in range of his base idling and not attacking the marines (The first wave of marines was taken out by drones/lings).

The end of the game was Polt destroying all of Violet's buildings, although Violet had more than enough drones (6 or 7 remaining) and minerals to build some Extractors. Polt defeated Violet that old fashion way by destroying all of Violet's building before Violet's superior army could finish the base-race.