I agree with you totally, with the limited 16 colour palette I was working with I have had a lot of debates of how to make them more readable.
My current implementation is on "easy" mode it flashes on the first time you come across an obstacle, and the instructions go through the different light levels to try and allow you to get use to them.
I could extend that to the "harder" levels, maybe with a toggle so you can turn it on and off, like "Help: On/Off".