I was there on 7/3 with my toddler and walked through that section, unfortunately only able to spend about 10 minutes. There were vintage arcade machines, pinball machines, and many consoles and handhelds on display. The arcades were playable and many of the consoles were also playable, though some were out of order. It was a large enough section that I probably could have spent an hour or two if I had the opportunity.
Overall, I thought it was pretty cool that it would warrant a visit, especially at reduced ticket prices. First Sundays at OMSI is $2 admission!
Add: they had pong on display and projected onto the wall. From memory, seems like there were many demo consoles of the Wii, some Kinect, and Sony Move. There was a display with a historical look of all the old Nintendo handhelds (game & watch series) progressing through gameboys and the DSes.