Shirou from the original is now a girl named Ayaka Sajyou, and servant Saber is a man (same hero though). There are many commonalities rules-wise towards how the Holy Grail War works, with the main differences being that in this version, the War takes place every 8 years; also, there is a whole new tiered system of masters, which follows the angelic hierarchy (there is more to it, but it was not really possible to fully explain it in a 12 minute trailer).
The art in this trailer is actually fairly good, and the short flashes of fight scenes, mostly between Saber and Archer, look great. The character designs are obviously nice and unique, exactly what you would expect from Nasu. There are a lot of similarities character-wise between Fate/Prototype and Fate/Stay Night, and a fan can instantly see how different characters here (like the crazy priest) were re-imagined in F/SN (Kotomine Kirei).The only criticism I can give is that the MC looks quite generic - nothing more than a typical, shy, insecure school-girl, at least judging from this short preview.
There really is not too much to say about this one, since it is so short. 12 minutes long preview of a project of such proportions do not do it justice. It is confusing, jumps from one thing to another every 10 seconds, but I suppose that is exactly what you would expect from a trailer.
Overall, I can sat that the Fate/Prototype trailer is quite enjoyable and it led me to take quite an interest in the Fate/Prototype universe. There is a lot more to read about it online and a whole prequel-LN series named "Fate/Prototype: Fragments of Sky Silver". So if you have some time, give this short preview a try, especially if you are a big fan of Nasuverse. One warning though - if you have never seen or read anything to do with Fate, you will most likely not understand or appreciate this.
