I haven't tried the game yet (definitely will when I have time), but just going of the screenshots I think you could improve the N64 feel a lot by adding a bit of distance fog (Hyrule Field in OoT us good example) and adding an option either to render the game at a much lower resolution or to downscale the image. The highest resolution available on an N64 was 640x480, which looks pretty pixelated on a large modern display. Personally I find that the low resolution works better for low-poly models, helping them look more soft and natural instead of flat and papery, but since some people prefer the ultra sharp high-res look I would make this optional.