I agree with Alturos on this I really love the melody you have going with your right. you should try adding a different rhythm pattern with your left hand a bit later on in the song to make it even more interesting for instance you could have a few pauses with your left where you let the notes ring out and keep playing the melody with your left or add a few extra notes to the chord (play it in double time).
But these are just some ideas, it's a great song. Would go really well for a boss level!