Anyone who knows me knows I'll defend Yooka-Laylee to the ends of the earth, but I gotta confess that the Tonic is a bit of a misstep for me.
There's a pretty big difference between playing on a real CRT television and playing on an HD screen with a dark grid on top of it. I never noticed the scan lines on my TV as a kid, but a dense overlay is distracting and just makes the game look darker.
If it turns out I'm misremembering what older TV screens looked like, and the filter is actually really accurate, that still doesn't mean the effect should be recreated so closely. The funny thing about nostalgia is that it's rose-tinted and you don't remember the bad parts, so if nostalgia is the goal of the Tonic, why bring the bad parts back?
I also think the 20 fps cap doesn't do the game any favors, for two reasons:
1) It causes the double-jump to be less responsive, I guess because that specific input doesn't get registered between frames for some reason.
2) Only the slowest N64 games I've played consistently run any lower than 30 fps. The frame rate might dip here and there when I play Banjo, but the vast majority of the time, it runs faster than the 64-Bit Tonic does.
Less important, but there's also something jarring about all the water in the game being completely untextured, and the HUD display and sprites remaining HD when the game's resolution has been decreased. Wouldn't hurt if the casino tokens, gems, pirate's treasures, etc. were also sprites. I can understand not every model in the game being recreated in low-poly, of course, because that would take way too much time for a bonus feature in an already finished game.
Don't get me wrong, I appreciate the Tonic as an option, and there's a good bit it does right. Although if it stays the way that it is, I don't expect to use it again.