It's an interesting attempt, i've wondered what DKC GBA would look like if someone tried correcting the palette somewhat. But unlike most other ports on the GBA, there are tons other problems that I feel makes the effort not quite worthwhile. Backgrounds are missing details, layers or effects. Day to night transitions don't exist anymore. And most of the graphical assets were resized to be 25% smaller than their original form. A number of the sprites are also missing animation frames as well.
I don't know how complete that shot is, but it also seems like the tilesets have fewer colors than the originals as well. Either that or there's something else wrong with the shading and overall detail. Compared with SNES-
Interesting regardless, and an obvious improvement over the stock GBA version. Though the sky is a bit odd (that one might be hard to fix as it seems to have a different gradient effect on SNES).