This was a quiet fun to play. Feels life this can make for a good mobile game. Maybe you should try making a version for that. I sometimes came across a bug where catapults became invincible but it was actually great. Good luck.
Thanks for your kind comment. The controls should be straight forward on mobile indeed.
You cannot aim a catapult, did you notice? You can only pierce through catapults by aiming an enemy behind them. This is what makes this enemy interesting in term of game-play.