Some states with electronic (i.e., computerized) voting machines are STILL so slow in posting returns to the TV news. Why such a lag? It seems like the old days, as if each vote is counted by hand. Does each vote have to be hand-certified as accurate, or what? 
Around here, the computerized voting replaced lever machines. In both systems, you just read off the vote totals at the end of the night, so I don’t think there’s any improvement there. The main delays are in certifying the results and in calling it in to the board of elections or whoever is tallying it.
I assume the certification is the real holdup when you see delays. They have a count, but there were irregularities of some sort, so they won’t release the count as “official” until they consult with some state official, and that state official is dealing with every other district with issues at poll closing time.
No matter what you saw in Heroes, every electronic voting machine is independent and not networked in any way. (If you didn’t see the show, Micah uses his power to corrupt the totals in all the voting machines. This was doubly wrong. Not only are voting machines not connected, precisely because of this issue, but New York State doesn’t have electronic voting machines yet.)
The votes from each machine still have to be individually delivered in some way to election headquarters and then assembled into a whole. Each district has to go through a series of procedures to ensure that the machines were working properly, recorded every vote, put out the proper tallies, got certified by the poll workers at the site, and then moved out. Once at headquarters, the votes have to be added to the proper recipients. It’s still a process, not a push the button result.
Organized chaos, from what I’ve witnessed. 
This is certainly not true, not in most jurisdictions.
Here in Hennepin County, and much of the state of Minnesota, the counter at each precinct was networked via a phone line to the central election headquarters, and reported the votes electronically. Now that has been replaced by a wireless radio transmitter built into each of the machines.
Those are only preliminary results, the printed out results and the actual memory from each machine is physically transported into election headquarters, and checked against the transmitted results before being certified. (But they almost always agree.)
Note that these are the results from the scanners, which read paper ballots filled out by the voters. The actual paper ballots are always there, and can be counted again if there is any question. In fact, our state auditing requirement randomly selects several precincts to be hand-counted & verified against the machine totals.
But having been on the Secretary of State’s committee dealing with voting machines, I have seen demonstrations of many of the direct-recording (paperless or post-voting receipt) voting systems, and they almost all have a ‘master machine’ in each precinct, with all the other machines networked to it. So it would be quite possible to hack that machine, and then infect all the machines in that precinct. (There are documents on how to do this for specific brands of machines floating around on the internet.)