Ok for those who don't know Hellsing OVA is a remake of the original Hellsing series but following the manga more closely as the origional series only followed it up till around episode 6.
Its suppose to be broken up in to 10, 50 min parts each telling 1 volume of the manga and so far 3 are out with the next coming in a few months.
If your a fan of Hellsing i def recommend you check this out as the original series was so good and this makes it look crap.
And for those who have never seen it, its tells the story from the beginning so you wont miss anything if you haven watched the original before.
Check out this vidp to see the improved animation: