This is really polished! My only complaint is that the obstacles aren't always very "readable" - some things that look like obstacles aren't, and some thing that don't look like obstacles are. I would find a clear way to visually differentiate the two.
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".