Hello, thought I'd respond to some things and show off a couple mockups for the backgrounds of the game.
So first off, some of you have suggested using a pink-ish colour for Mario, this is something I looked at before while drawing these, however I was never a fan at all of how it looked as without the shading it just seemed kinda ugly to me, as well as causing the enemies to become miscoloured. But for the sake of comparison, here's Mario using a pinkish palette:
Perhaps some of you prefer this look, but personally I think that red is a better fit here and is more inline with the other NES Mario games, but each to their own.
Secondly about Yoshi's colour changes, as Lusofonia pointed out, the 4 sprite palettes I have chosen are very much intentionally designed for this as they will allow for all 4 colours of Yoshi and koopa to be possible at any time without colour clashing. Instead of swapping a single palette dedicated to Yoshi, Yoshi will instead swap between palette mappings selecting one of the 4 palettes for his primary colour, the same is true for the Koopas.
As Sics question got me curious about how this should be handled, here's Mario and Luigi on a black background with a slight palette tweak so they don't disappear and one with their standard palette:
I think simply switching to using this alternate palette in areas with black backgrounds will be a suitable solution to the issue, there shouldn't be too many instances of this change other than in castles anyway.
And I also made a couple mockups of how the game could look, these only cover the first stage/tile set, but this is my vision for the game:
(I later noticed I slightly messed up the top of the hills and the HUD isn't perfect in this, but the actual backdrop is as I intend it to be in game. The numbers along the edges are just used for me to keep track of attributes while making these, they aren't a part of the game obviously)
And a larger mockup of the first stage:
(the final results might look slightly different to this but overall it conveys how the game will look)
And lastly, about the [?] blocks having sprites, the blocks and coins will all be background objects as they are in the other Mario games, the sprite present in the object banks is for when the blocks are hit and get bumped upwards, much like how the real Mario games do it. When hit the blocks will turn into sprites briefly to perform this animation and then return to being background objects. Due to colour limitations the appearance of the blocks may vary slightly in some stages, this mockup shows the least colourful variant, however if a stage were to have a totally black or predominantly white background then additional shading may be possible. (the shading colour has to be omitted in some instances so that the sky colour can be used behind coins and flip blocks)
Anyway, thankyou for all your responses and for reading my posts,
I'll catch you all later, take care!