Beautiful game concept. Although try to make different type of maps, add more details to the maps, make some traps perhaps? Add some powerups, or level XP, or talent points. New types of guards that does different things. A much bigger map, hmm since killing the target is easy maybe make him defend himself a little bit or something? Try to add a story to the game and make sequels with new content. Thats all the ideas i can think of, but I totally enjoyed your game! ALSO try to add unique missions, for example making your character do an specific action before completing/killing the target. Awesome game!