Really liked the macabre vibes with the choices of color, textures and shades.
Think the N64-like animations were on point, with those ever so slightly truncated or skipped frames (as I'd describe it) and somewhat lack of smoothness, in this case intentional as I see it; those polygons with many flat surfaces and limited use of curvature (baring exceptions) were also pretty recognizable + the pixelated texts and other details like the aesthetics of the "user interface".
For the writing and the story, I really liked Nancy's personality (e.g. her taste in chocolate and the way she often has her eyes half-closed) as well as the other characters' and how that was expressed, plus the pacing of the narrative and the whole 1st-person camera fits well with a video-game vibe again, IMO.
A lot of this animation seemed to be a homage or inspired by N64 games (although still with its own identity), but I wouldn't mind a bit of straying away from that just so to make it something even more unique; perhaps more exploration with the camera angles instead of the either 1st person or the "expository cutscene" one (as I'd call it), or maybe showing different ways of how Nancy advance through the environment instead of always 1st person walking; I realize changes like these could make it less recognizable as a game/homage, so I suppose it's about what choices you want for the throwback and which ones you want when it comes to expressing your own identity (when deciding that, I'd advise you to follow your heart, naturally).
Also, loved the disguised kid, hehe.
Overall awesome, solid stuff, I would love to see more.