Really creative idea for a game! Never have thought about changing the rules of chess like this. Works really well with the black&white constraint. So far I have only tested the game against myself because I did not have an opponent at the time of testing this, but maybe later will test with a friend to see how the game actually plays. It's clear that the territory control aspect changes the game very much from what the traditional chess is.
Is it supposed to be possible to take back selecting a piece? At least, I did not find a way to do this. In case it is not possible, this can result in a situation where the game cannot continue if one has accidently selected a piece that have no legal movements.