I like the idea. First, it was cool to incorporate chess pieces. Second, it was good to make me avoid controlling the point instead of capturing it. And as far as I have seen, it was actually hard to do.
I like the conflict you created with building walls: you want to kill enemies to earn money but you don't want to capture the point. It definitely added some depth to the game.
The game was pretty smooth to play (except having to re-launch the game to restart). The graphics could use some tweaking but it is fine.
The cards were not too influential, all I did is basically avoided pawns (as they break the walls).
One issue I see is a lack of variety. I've completed the game once and I don't think I want to do it again. Perhaps adding some levels with pre-made walls or other stuff could make it better.
Overall, good job!