Yes, that's an Atari 520

Or in that ballpark. What you can't tell from this shot is that there
are about twenty more if these, and they're networked together for a
game called Midi-Maze. It's essentially a 3-D maze (looks much like
old maze screensaver from Windows 95 days) in which you are a colored
smiley ball, shooting at other colored smiley balls. Yes, very old
school deathmatching.