Adam uses a carousel-style slide projector for Barry's talent show performance. Carousel slide projectors are incapable of the instant photo transitions seen in his slideshow.
Beverly's Hanukkah sweater contains modern LED lights, which weren't available in the 1980s.
According to the opening voiceover, this episode takes place on December 13, 1980-something. Hanukkah never began on December 13 in the 1980s.
This episode is supposed to take place on December 13 in eastern Pennsylvania, but when Pops and the JTP are on the baseball diamond to map out the Who's on First? skit, there are trees with green leaves. Trees would have lost their leaves by the middle of December.