This game offers such an absorbing gameplay experience! I'd add some sort of more in-depth tutorial to prevent people from giving up before understanding the game.
I think the font is not appropriate for your UI since the coordinates are super important to the game play, especially because you used 0 and 8 for the coordinates, and it can be tough to differentiate between the two numbers. Personally, I like using the fonts created by Void for smaller resolutions :)
Overall, this is an awesome game and I'd surely go back to play more if more content is added.
I love your 1-bit style, keep it up <3