The colour changing is linear, in that box in the lower part of the screen is something I called the "elements wheel" (I thought of the colours representing earth, fire, water, and air and eventually there might be better graphics to reflect on this), and the wheel is constantly turning and every time a different element gets to the (invisible) trigger object, a colour change occurs.
Right now the only things that get more difficult on higher levels are the amount of energy you lose for hitting a stone with the wrong colour or a stone reaching the target row, and the amount of hits you have to score for the next level...
As for the "H for Help", I was running somewhat tight with the space so I had to stay terse...
I could change it like this, but shortening "Escape" to "Esc" alone didn't cut it for "Instructions" not to drop into a third row, and "Esc" being so far away from what it does appears to me to be a really bad thing...
What I can do is put the info at 80% font size...
