The obstacles in the swamp level of Reptile Roundup are difficult to differentiate and hard to see. I only have a slight issue with my vision and even for me, it's difficult, can't imagine what it's like for someone who's only partially sighted. I think adjusting the colours so the obstacles aren't as similar in colour to the background would help this issue a lot, as I don't feel this is a problem with any other level.

Here's an image to show the colour issue when compared to the Underground Tunnels and Shrubland levels.