Around 1980 I bought a hand held space invaders game. It was about a foot by 10 inches and worked on C cell batteries. I got it for my Daughter but tried it myself.
I found it sort of hypnotic, playing it for long periods.
A few months ago she wrote me that she had found that old game in the attic and let her kids play it. It still worked and again she said it sort of hypnotized them.
I have the Donkey Kong version sitting on my office shelf. Non-working, sadly.