Pick up a game.
Take it apart.

Ghost targeting & state machines

Pathfinding & risk evaluation

Language parsers & world state

Ray casting & 2.5D rendering

Fixed-step physics & paddle collision

Discrete logic, overlays & human rules

Parallel pins, serial bits, ADC codes & HID reports

IR imaging, blob geometry & pointing reconstruction

RC charge curves, comparator thresholds & timer quantization

Light pens, flash detection, raster sync & display latency

Accelerometers, gyroscopes, drift & complementary filters

X/Y DAC deflection, beam blanking & phosphor persistence

Clock dividers, square waves, LFSR noise & mixing

Quantization, aliasing, DAC steps, DMA refills & underruns

Address lines, chip selects, mapper registers & ROM banks

Capacity, access time, installation & player-visible loading