Wow! What an arrangement!
All the instruments and orchestration scream "spooky"!
Big Danny Elfman influence I guess.
It's just splendid. I listened to it several times because I felt the meter was strange (3x4/4 + 5/4), it adds that uneasy, unstable aspect perfect for a spooky boss.
There's a lot of good stuff in your composition. The intro sets the mood right away, and the build-up is fantastic.
In short, it's all good.
One small point for improvement would be the panning: the double bass pizzicato is too far to the right. For headphone listening, having the bass off-center unbalances the mix.
What do you think? But as the French say: ça déchire!