Sound!!! I’m using TrackerBoy to get authentic sounds and splitting them up by the 4 channels.

Accurate to real hardware each channel can only have a single source playing at a time, so if you notice you don’t hear the bottle shaking sound during an explosion.

This then leads into that really cool accidental auto-ducking that retro consoles had when sounds cut out portions of the music track (whenever I learn how to compose that)