Tempest in transistors only
Ok, maybe we got to stay in the world of reality. Perhaps a simplified version of asteroids, where you either stay in the center and shoot in multiple directions moving/approaching dented/spheres/ovals/maybe rotating of a few sizes. Say 8 play-field objects.
-or-
Have a play-field of multiple spheres bouncing around, alternating trajectories off the 4 sides of the scope, and you, need to maneuver out of the way with an x/y paddle running against a clock. The highest time wins...
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16 play-field objects, 1 player, 3 bullets, 12 asteroids, 4 of 3 sizes each. Skip those silly alien saucers.
I could imagine GK creating one of these 2 games transistor only using the existing functions in the pong game.
GK, pull off one of the first 2, and you blow everyone away. Pull off the third one and you will be the GOD of the transistor only video game, no one on earth will touch you. (Variations on the how to multiplex the ball oscillator, mixing in a bit of the triangle and square wave to make a ragged edge, or, shooting the asteroids would instead of destroy them, just push the away from your shot. You don't need to make a perfect asteroid game simulation, just a game you can play with maybe even 2 players which is much more interesting and complex and fun compared to simple pong...)