Oh, the memories! The art style fits very well with the DK series, especially the jungle locales. I also love that the silhouettes still indicate which characters are featured. Some of the greens could have a little brighter, like in the game's jungles, and some of the plants at the bottom say more "forest" than jungle, but overall I would say the coloring is very well done. The piece says 'lush" and that is exactly what I think when swinging through Donkey Kong's jungles. Maybe in the next posters you could choose to feature a few of the enemies hidden away in the foliage.
I actually like the, almost, monochromatic nature of the artwork. The use of purple and turquoise give it a surprisingly nighty feeling. Not sure about the rain though. The way it bends is kind of strange looking to my eyes. Overall great work! Not quite the feeling I got while playing Donkey Kong but, in it's own merit, quite atmospheric. As far as video game art is concerned, it's top notch. The lower portion of the painting is most appealing. The way the color blends creates an, almost, clear picture but if you isolate parts of it you get a kind of color pallet, smudgy effect that is very appealing.
I'm amazed at how detailed this is, I feel like there's so much to look at in this picture. I really like the sense of depth here! It's interesting, too- I get the feeling that the lush environment is more the focus than DK and Diddy, which is pretty unique for fan art. Or at least I think so :3
My only critique is that I feel like this could use some more contrast, some deeper shadows. The colors blend together a lot, though it does suit a dark, rainy atmosphere.