Very nice entry!
I love the old NES aesthetic and feel also and I think you nailed it, even down to the controls and delayed attack, etc. I love how the actual QUACK onomatopoeia itself is the attack!
The only real nitpick I have is that I think you should put a little more color on the levers to designate them as something different. I missed the first one and ended up searching all around and even backtracking all the way to the beginning to try to find what I had missed.
Music is fantastic btw! I wish this jam had us grading graphics, sound, music, etc also. Between it and the aesthetic, it actually reminded me of Duck Tales a lot!
Almost forgot to say that I love all the stats at the end also. I think that this game would be fun to speedrun and also to try a pacifist run on also, especially if you add seconds to the timer and add an enemies counter stat also.