they registered people to other political party affiliations, at other addresses.
People showed up to vote, and weren't on the rolls. They said they voted there many times before, but that didn't matter. Some left without voting, some insisted on voting and voted at what they thought was the correct district with provisional ballots. Ballots which were then tossed, because the voter was in fact registered to vote elsewhere. All provisional ballots aren't bad or useless, but the felony re-registration scheme from Sproul's people made those ones useless.
The confusion this created backed up the voting lines. And there were official repug party Poll Watchers in those same targeted districts, who were issuing challenges to a bunch of voters, at the same time, in synchronicity with Sproul's efforts, which backed up the lines more. So Dem heavy precincts lost people at the back of the hours long line, who couldn't stay to vote, and they lost people who tried to vote all day long, and wound up casting fruitless discounted provisional ballots.
You're right, they also did toss new registrations in the trash (a felony), and they did use the re-registration to create more ghost repug #s, too. I don't know what those assholes are pulling in '16. I've been looking for info or signs of what they're up to, they're obviously doing some thing the repugs think is worth paying for.