There were some ups and downs, and I did have to re-read some things to make sense. But you can fix that. 

THE BAD

 1: Sense. Some parts of your story just won't make sense. (sorry, but you can fix that.) Like the fact that there was a simple WRITTEN test for the teachers with questions even a first-year could solve. And of course, Harry's hot-headed nature. Change that a bit?

2: Cover. The most important part of the story - Maybe go to a nice cover shop or make your own? :)

3: Minor mistakes, but I did talk about them. There weren't a lot - just two.

4: The third chapter's name doesn't make sense, (though its an actual dialog, but still) and the title of the book should have capital letters. (like the title of this chapter)

THE GOOD

1: The plot is amazing. I love the whole idea - and the marauders, of course. But why did Harry become a teacher?

2: Detail. The story is detailed, and I like reading it. 

3: Un-put-down-able. I could go on forever but I can't. School really is a terrible thing. 

4: Great as a fan-fiction. Since it's a fan-fiction, I suppose you won't have to think much. (lol) Don't forget to add Severus though!

The dialogues aren't too long, and the detail isn't boring. The characters are well-developed. (expect maybe Harry.) The story's a bit too fast though, so add in more detail. Although that's optional. 

The blurb of the story is fine, but the title sounds a bit boring. Make up something to do with the Marauders - Harry Potter and The Marauders or anything else. (I can't think!)

The review's short, I know, but since it's a fan-fiction, I can't tell you to change the characters and all that. (Though they don't need changing.) If you ever write another one, write one about Snily. (my ship.) 

                    PROBABLY THE BEST HARRY POTTER FAN-FIC I EVER READ.