The combination of the genres worked very well for me, especially with the four enemy types; you managed to implement some more than solid level design thanks to that. :) The pixel art was fantastic as well! I was wondering if you took some inspiration by an old Ludum Dare entry by deepnight, called "Proletarian Ninja X"? It was a bit more action based, but your two games have the same basic premise. :) Anyway, it was a great execution of a neat idea, so I'm glad to say that I included your game in one of our compilation articles about the Ludum Dare 41, as well as it's featured in the related gameplay video. <3 Keep up the good work and good luck with the ratings! :)
Best wishes,
Sebastian