I'm duly impressed by this so far!   You've created a brilliant Snape who keeps his motivations for everything that he does close to his chest, as well as a vulnerable yet strong Harry who hates these confrontations with Snape but yet isn't afraid of them.

I must say, that Severus smiling into the fire when thinking of Lily's death was just bloody cruel.   And his comment of her dying beautifully... I couldn't determine if he said that out of malice, or admiration.  Only Snape (and you) knows for sure.

Great job so far.  I hope to see an update from you soon.

Yes this was very enjoyable. I hope you update soon!