Thank you for the comments and suggestions. I edited the house a bit and I may try to make more changes later on.
Good: atmosphere, simplicity, efficient barest suggestion of grass texture =)
Could improve: more detail and volume to the house such as shading under roof edges, recessing door; add some wear and tear, a chimney. Dithering between grass shadow rings could be more irregular and texture-ish. Rings themselves are too even in shape and width.
There might be a (very) little more grass detail yet, a flower or two; and ripples on the water around the poles. Lines on the house and pontoon look jaggy: on the house side and roof, you could use the jaggyness to suggest worn planking; on the house front and pontoon, the lines just look broken for no reason, and it would take masterly anti-aliasing to make them good at that shallow angle. I'd suggest to cheat perspective and make them straight on the pontoon, and a little more at an angle on the house front (or straight too).
Palette: you need to shift the hues of the colors in each of your separate ramps, to mingle the ramps more, and to mix the ramps throughout the piece (instead of one object = one ramp. If this is not clear check the Syosa interview in 'featured artists' on the home page).
I like the simple style, but the house is not shaded. I personally found that ruining the image.
Thank you!