While this is interesting, the project page is a little light on what it can do. Can the RPi feed streams of instructions to the N64? Can it act as a co-processor?

EDIT: more info on Twitter apparently: https://twitter.com/kbeckmann/status/1539738410063208454

There are a bunch of potential ways that could go with varying levels of interest to myself.

The PIO of a Pico is quite fast and could theoretically be utilized to pretend to be a specific chip. The question is at what speed. That's what would interest me the most. It would be a fun project to make a Pico pretend to be an SRAM and measure what kind of access speeds it could support. If could be fast enough to hack into old 8 bit machines you could make some awesome Frankensteinian creations.