When I try to download it just says "invalid game" in a popup.
Most likely issue is you might be using the wrong color expressions. There is one that takes values from 0-100 and one that is taking the classic rgb values from 0-255. So if you think you are using the 0-255 but the expression is using 0-100, the resulting colors will be brighter than you'd expect.
rgbex uses 0-100, rgbex255() uses 0-255. rgb() is deprecated afaik.
construct.net/en/forum/construct-3/general-discussion-7/rgbex-misleading-155134