Am I the only goofball that can't figure out how to play any of the games in the list? Went straight to Alcon to relive my youth and couldn't figure out what the keyboard controls were.
From the article: "In general, pressing the 5 key will insert coins, 1 and 2 will start 1 or 2 player games, and the arrow and spacebar keys will control the games themselves."
I had similar trouble. After a few reloads, it showed a screen with the keyboard map, but for some reason that element was hidden on the other reloads. So I guess my tip is to look for a hidden element.
Pressing tab (when the canvas is the focused element) should bring up the emulator control screen, where you can see and modify the controls.
I love that Internet Archive is doing this, but I have no idea how this isn't running a foul of copyright laws.
The IA was officially designated as a library by the state of California in 2007.