I have a single-player Williams game that I bought 25 years ago. It was 10 years old when I got it. It's all electro-mechanical; solenoids, relays, and a big rotary switch. Not a printed circuit in sight! It works as well today as when I bought it. The only thing I've had to fix was the shaft that runs through the big rotary switch. It wore out and broke, so I replaced it with a piece of threaded rod, and it works fine.
The settings for scoring free games are done by changing wire jumpers inside the box. It even came with all of the manuals and score cards for the different award settings. There are some adjustments you can make on the playfield to make it harder or easier to keep the ball in play.
I mostly like the noise the thing makes. All of the relays, motors and solenoids make a hell of a racket...