I’m guessing in the end I would end up animating the water horizon with a sine wave and then using pal or something to darken any colors under it but was wondering if there may be an easier way?

Thanks!

I think the most relevant thing to what you're describing is probably the bitplane masking features? They're not in the manual, but the 'Hardware state' section of the wiki page on memory has some information.

If you did use that, you'd set up your palette so that, say, colors 0-7 are underwater versions of colors 8-15, and then after drawing the screen, you'd set up your bitplane and rectfill() the underwater regions to change the colors.

Oh that’s wild, thanks so much. I’ll use this as an opportunity to learn more about memory in PICO 8, I feel decently comfortable with Lua but I’ve been intimidated by that stuff lol

using screen rebase + palette shift is also a good alternative (without breaking your palette like bitplanes)

• draw game as usual
• use screen as spritesheet "source"
• use sspr to draw portion of screen to itself with a modified palette

That sounds like a clever idea as well, I’ve only experimented with sspr to scale Sprite sizes but I’ll try this too to see what might work best, thanks a ton