Thanks for all the feedback!
The ground is almost identical to the start of Gimmick level 4. Definitely too close for comfort. I tried several times to make it more cartoony, but it ended up looking awful every time. I'll be giving it another shot for sure.
The ladder was based on free art by surt, which is in fact lit the same way. It looks like the front of a flat step to me. But Drag is right, it doesn't really fit the theme in the first place. I wanted to avoid vines, but I can't think of anything else I could use instead. I do plan on adding more man-made structures eventually.
The bushes, platforms and clouds are entirely my fault. I kind of like the bushes, personally, but every time I look at the platforms I see the watermelon block from Minecraft.

I don't even know what they're supposed to be, I just needed a one-way platform that's visually distinct from the ground.
tokumaru wrote:
The character looks pretty cute, but since it uses 4 colors, you're gonna need overlays or two similar palettes (black, white and green + black, white and blue) to be able to draw it like that.
It's the latter. I spent four days getting the head and body neatly split into different sprites, just so I could get four colors with only two sprites per scanline. As a bonus, I can also shear the sprite horizontally to make her lean forward while running, without spending any extra tiles.
The colors shown here are pretty much random - the idea was to pick palettes that could be shared with enemies. Except I don't have any ideas for enemies yet.
I'm a programmer, not an artist, by the way. The technical restrictions are what got me interested in the first place.
Dwedit wrote:
Looks like an alteration of Super Mario 2, a little too close for comfort.
That's actually the look I was aiming for, within reason. That said, I didn't use any SMB2 art for reference, so I guess my subconscious knows something I don't.