Great work I forget how addictively fun TD games are.
Needs a Sfx for losing a life with it's kind of zen / oriental style music maybe a gong.
Maybe the option to sell towers or pay to have them moved would add a bit more flexibility. Nothing worse than setting up an ideal pawn killbox and have knight just gallop through without the ability to sell towers and build a last line of defence.
Mouse over info could be improved e.g. mouse over tower shows a towers range or stats.
Maybe new pieces that can actually attack towers?
The black and white works but could a hint of colour e.g. 4 colours black, white, red, green work and fit within the cards/chess theme.