Thank you! That's a good point actually, in the very early stages of developing this idea I thought about also having matching symbols that corresponded to each colour display on both the collectables and character to make it more playable for people who are colourblind.
Now that the collectables are gems, I think maybe making them different shapes for each colour, e.g. all greens are triangles, all blues are diamonds etc, and then have the target shape appear on the character would perhaps help with this. I think with more time I will implement something like this in the future.