The Ninja King is dead! Finally. This took me a while :D
Overall it's a pretty nice game. I love the pixel art, the music and the general composition of everything. It was really cool. It took me a while to understand the game but then everything worked fine and I could finish the game an destroy all enemies.
What I did not like and this is highly subjective: After every boss all my Mercs were gone and I had to rehire everyone. I would have preferred if I could have kept them and the game would have not slowed down in these moment. But I enjoyed the visual and the music while waiting, so this is fine :)
Good job!