I love the retro theme of the game, this not only visualizes well in the art-style, but also feels great in the gameplay & sound. The latter is what intrigued me the most about your game. The audio transitions when you progress are super smooth, as well as the transition when you die.
I must admit, the hard mode is a little too hard for me, but that is mostly a skill issue haha.
Despite my previous comment about the sound transitions being really smooth, I would really love to see the animatronics spawn in such a way that they come to the player when different beats drop, I think this is some extra player feedback to hit those "perfect" smashes.
What did confuse me a little bit when I saw the game was the UI indicating the button, as well as the mouse click. This might seem like a bit of a stretch, but I would consider creating some sort of combo-system, where different animatronics might require different buttons/combinations?
Despite that, I think you can definitely be proud of what you've made as a team this jam! Keep it up!