"Failed to create a new color. Please try again. Error: Hourly limit exceeded. Please sign in to continue."

The overall concept is not bad (a bit bland) but seemingly tying in color combinations attempts behind a login (or I suspect you send the color combos off for answers somewhere else if its valid or not instead of having them programmed in) is pretty crummy/sloppy.

Edit: forgot to include that once you get multiple colors the process of having to constantly re add the color you are mixing with another color is extremely tedious. I would think that the colors shouldn't auto clear every time you mix and instead just let us replace one/both manually.

edit 2: I don't see a login option so I am assuming you are just taking each and every color mix someone does and sending it off to somewhere else for an answer. That seems like a pretty awful design mechanic and seemingly abusing some other sites system.