Hey there - sorry for the incredibly long wait, RL decided to interfere with things and made stuff incredibly difficult for a while, but I'm back now! :)
I really enjoyed this, tbh, which I don't usually say (mostly because I don't usually read Snape/Lily, whether unrequited or not) since I don't often find something like this I like.
I liked how you went through the time when he first lost her, in a sort of permanent matter, to James and the light, and up to when he lost her literally permanently, when she died. I don't know if that was why you chose that snippet of his life, but I love the sort of symbolism between the two times, and it's definitely the time where he develops most as a person. Also, permanence with the idea of infinity is a pretty interesting combination - infinite combinations, but a permanent loss.
I think you did a really good job of dealing with Snape in this one. I like how you don't shy away from showing that he's petty - how he refuses to say Harry's Lily's child as well as James' - and bitter about what happened, but contrast it with him being upset that it did happen and regretting it. It's a powerful combination of emotions, but you handled them really well and they worked together brilliantly.
Again, I like how you mark out how he always thought of her, despite what he was doing and where he was and that he'd lost her - it seemed to me that you really hit home on the idea that he hadn't really lost her forever yet, even after his mistake (or, at least, he didn't or didn't want to think he had), but then when she died, it was all over and there was no going back. It's a very sombre thought.
The style you wrote this in is lovely. It's very simple, fresh, plain kind of style and I really like it. I think it works so well with the level of angst in this, and just all the emotion Severus is feeling. It lets the emotion take the front seat, so to speak ;)
I'm so impressed you wrote this in five hundred words, as well. I could never, ever do that. I would fail spectacularly, I'm sure :P So yeah, well done on that front too! :)
This was lovely, very thought-provoking, such good characterisation, perfect style choice and writing, and really, really angsty... I might need to go and find something cheerful to read (you've actually effected me with this, haha, well done!).
Really enjoyed it! :) Feel free to request something else in the future!