If anyone has any questions about the engineering process/game itself I'd be happy to answer.
How do you handle the interaction between 2 pieces being moved at the same time ? Can I dodge a capture by picking up a piece ? Say 2 rooks are facing each other, how do you handle a mutual capture attempt ?
I have solved this problem, but still in a turn based setting :
* Both player choose their move, and moves are resolved simultaneously
* A piece cannot be moved 2 turns in a row (discrete cooldown time)
* When 2 pieces land at the same place, they are both considered captured.
* If they move in straight lines, in opposite direction, they are also both captured.
* NO CAPTURE for pieces crossing each other path / knights can exchange their positions.
* No pat. A player can skip his turn.
* the goal is to capture the oposite king obviosuly, not to checkmake it.
With a low blitz time, it solves the same fundamental problem as RT chess, but it can only be played online.
From a few test game, it looks like basic chess structure is preserved. But then there is the question of finding the Nash equilibirum of the game ! 2by2-simultaneous-move-chess with both rook and king leads to some sort of rock-paper-scissor.