Mouse sensitivity issues aside, I like how there is a complete story in the game. It may have a surreal plot, but that just adds to the game. It's good that you have a different sound effect for when the player runs out of bullet. While the game is fine, I think the theme interpretation is too loose for this. I didn't even know there is a slide button and the game works fine without needing to use it. I suggest trying to integrate your unique mechanics more deeply into the core gameplay so that the players need to use them to progress.
Still, great job overall!