In all fairness, I haven't been able to play it multiplayer myself, and even I'm surprised by the singleplayer stuff, and I'm probably even more surprised than you about the fact that this somehow is playable.
The kazoo music not being quite synchronized was, as you may have guessed, unintentional. At one point, I was considering making each instance randomly offset the kazoo music a bit, to ensure that they would be somewhat unsynchronized, but I eventually decided that it would just be a bit too annoying even for me so I chose to not do that. And I guess that was probably for the better.
The intense explosion effect was partially out of laziness. I recycled the explosion noise from another game of mine (Muffin Mania), partially because my voice was in a bit of pain and I didn't want to try making another improvised explosion noise, and partially because I knew that explosion noise had quite a bit of impact to it (after all, in that game, that explosion noise was the 'game over' noise) and I wanted the explosion in this game to feel like it had some impact because, y'know, you've just smashed face-first into an Inconvenient Space Rock (in space). Apologies for the jumpscare though.
I'm glad you enjoyed the game!