A couple of really close matches this time around. Super Metroid barely edged out Megaman 2 to see it go, and A Link to the past edged out Street Fighter 2 in the winners bracket by only 7 votes.
Sim City, having won two matches in a row including one against the highly regarded X-Com, got totally thwomped by Tetris. And many of the early upsets are rallying in the losers bracket, like Civilization, Mike Tyson's Punch Out, Chrono Trigger, and Tecmo Super Bowl.
Here is the link to the full bracket
Edit: Please note that Street Fighter 2, Contra, Sim City 2000 and Final Fantasy VI all have a bye to round 5 in the losers bracket.
And without further ado, round 4: