All people should be able to see and play your games so using the correct contrast for colors is essential when people need to be able to read or visualize what you want them to. Using a simple text and color contrast tool, you will ensure that your game will be able to reach the highest number of players, without isolating, those with visual impairments.
The text should be high contrast against its background (light on dark or dark on light). Use the Wave Contrast Checker (external link) . To ensure it is between 4.5:1 and 16:1 (over 16:1 cause issues for person's with light sensitivity.
Go to the text part of the I-SEE-U Blueprint to get techniques for making your contrast function for all people.
Use the Color Pick chrome Extension to pick from your images to test them.
Go to the Image part of the I-SEE-U Blueprint to get techniques to make your images accessible.
Review this video for an example of image contrast needed and how to use the WebAim Color Picker
Aim for 3:1 contrast ratio for important images.