Previously on HN: https://news.ycombinator.com/item?id=37381407 (2023-09-04, 385 points)
That demake does seem more like an (unofficial) port that preserves much of the original game play and style than most other demakes. (Disclaimer: I haven't actually played the game, I only watched videos.) How much would be achievable in the theory? Would it be only limited by the cartridge storage?
But the N64 version's assets will take up a lot less space, audio quality (if anything) can be dropped, etc. I'm sure they can make it fit.
I don't know anything specific about it, but given the cartridges were hardware, couldn't you theoretically bank switch to get any size you want?
Then you have to do a lot of work to actually manage those banks. Switching banks is kind of expensive, so you need to optimize your memory layout to minimize switching. Then you have to actually manage those banks at runtime.
Really, it's impractical to have more than a few banks. Expanding the N64 out to 64GB is just ridiculous. At that point, you'd be better off putting a modern CPU in the cartridge, emulate the game, and just use the N64 as a glorified display adapter.