Thanks! The art is all by me, I'm not a pixel art expert, I just manage decent stuff, but that took too much of my time and at the end there wasn't much time remaining to refine it and balance the economy. If you manage to have decent and balanced 4 or 5 waves, then you can just spam knights and win.
Lesson learned, I'd probably make a short post-mortem post about the game. Thanks for taking the time to play it!