I didn't think I'd like this trope. In fact, the whole Snape-is-really-Harry's-father thing still doesn't really do it for me.
BUT!
This was a good story. The writing is very tight - no long off-topic tangents - but enough detail is conveyed for the reader to get a good image. A lot of different ideas often found, and overdone, in fanfiction are touched on and explored but not pushed centre stage to the detriment of the plot. There's some pushy, tattletale Hermione...yet she doesn't get villainized. A bit of jealous prat Ron...but again, not villainized. A fair bit of Harry befriends Draco, with even a bit of flirting...but no romance, to my great surprise, emerges there. I liked the touch of bad boy Harry smoking muggle cigarettes and wearing tight leather pants; I also like the way sexy Harry walks the line between "yeah, okay" and "he's sixteen!"
Snape is a decent father but nowhere near perfect (like, seriously not perfect). But it works and the explanation of how he became Harry's father is decent.