Alrighty here it is the big review. Now I will preface this by saying that this is a review and so there will be both positive and negative aspects to it.

I enjoyed this fic. I really did and I believe it is certainly one of the more unique plot ideas I've seen in this category. You didn't go overboard with the plot as some fics are wont to do and you didn't mess with the development of the canon in an unbelievable way (i.e. they were soulmates all along or one of them was a Veela or she was a secret Riddle all along or some nonsense like that which doesn't flow organically).

You made a single, simple change (Snape's gender) and let it ride from there. Almost everything felt natural and I enjoyed that immensely.

The pacing was good for the most part although there were a few times that it did falter and I struggled to keep up or where it dragged slightly.

Your characterizations were on point for the most part and that shows an understanding of rather unknown characters that is quite impressive.

The writing was excellent for the most part although there were a few minor mistakes here and there. One which kept on showing up was that you never spelt 'shield' correctly. (you kept mixing up the 'i' and 'e')

I also felt that you waylaid the resolution of Potter and Snape's school differences. I'm not saying that you ignored it but you glazed over it in order to move the plot in a different direction. On the one hand I get it as this is not a dedicated romance fic and so their interpersonal relationships would not be a focus but on the other this is supposed to be a drama and that is prime drama material there.

They kind of jumped from outright enemies to hated allies to in love and it felt a little jarring. Now the premise you set for that was that it happened as a result of them both loving the same girl (Lily). That's fine and a tried and tested method but that also fizzled out as James never got the same opportunity that Snape did.

I did feel the romance was a bit flat to be honest. Something used to get to the next plot point than an actual relationship.

I was also not too impressed with the myriad of bisexual relationships going on. I have absolutely no care in the world about such things but I don't think the fic handled it well. It came across as being used as an excuse to have everyone hook up with each other just for the sake of it. The bottom line is that James/Sirius and then Lily/Snape to Snape/James felt a bit forced in.

Again I honestly don't care too much about who is with who but for the purposes of the plot it felt like it was either forced in or used as a convenience tool.

I also felt that the entire plot point on the life debt was a bit oversold. Could've been used as a romantic subplot or a dramatic one. A reason for them to be in proximity with one another.

All in all. I liked your fic a lot.
I do wish there was more drama between Snape and Potter and a more intense romantic connection than the 'shrug shoulders and get on with it approach' that was written.

The overall plot was excellent and the Arthurian references were awesome.

I'd give this a solid 8.5/10 for being a drama fic and for plot.

I'd give it a 6/10 for romance and overall relationship development.

I think that you should be very proud of this fic when all is said and done. Keep up the good work.

Good work as seems to be the norm. Well done.

I normally give my full review at the end of fics like this one so until then you'll just have to deal with the classics.
So here comes another one.

Good job!

You've taken this story in a very interesting direction. I am loving it so far and am so curious to see what happens.

She was petty.
Very petty.

I think we can all agree that a petty Snape is an awesome Snape.

Keep up the good work.

Great stuff. Healing the rift between them is gonna be slow work but so worth it I think.

Ladies and gentlemen... we have interaction! To the next chapter!

Ooooh do I sense the Shrieking Shack incident coming up?

Very nice but it begs the question. Imperio is an Unforgivable. Surely even that is crossing a line? Enough to warrant telling a teacher?

Potter Snape on the way please! The plot is surprisingly advanced for a fanfic. I am enjoying it thoroughly.

Cool stuff. Was that the alternative for the Mudblood mistake? If so then I think you achieved a similar effect.

Interesting. Now will this borrow elements of canon or are you Star Trekking it into unknown plot regions?

Wow... it's going to take a lot of work to fix those two. I look forward to it.

Very nicely done. I'm curious to see how you would handle the relationship change between Potter, Evans and Snape.

Hmmm... I smell potential. A lot of OC's thrown my way for a first chapter but considering how little we actually know of the characters from that period it makes sense. I must say this is a novel idea and I am very keen to see where it will lead.

The writing is excellent so far.

Good job!