The Darkstalkers OVA is actually called Vampire Hunter: Darkstalkers Revenge, which is also centered around the 2nd game of the series, with the same name (alternatively just called Darkstalkers 2). It's a movie divided in 4 OVAs, each being 40 minutes long

The OVA looks forward to explain the plot and develop the characters in ways you couldn't do in an arcade run. Another thing to point out is that regardless of how goofy they end up being, its battle choreographies do their best at portraying the characters' moves in the game.

Now onto the main plot (roughly translated, I couldn't get myself to fully type it out in my own words)

The Darkstalkers are creatures of darkness who have invaded the human world, getting rid of the sun and therefore causing a crisis for the humans who live in it, constantly seeking for resources and trying to attack the creatures. Donovan has demon blood on his veins, but he denies his origins in order to stop with these creatures of darkness. After saving Anita (Who back then would be named Amanda), he travels along with her to the dark human lands invaded by monsters that are pursued and hunted by different defensors of the humans, like the sisters Lin Lin and Rei Rei... but there's something even darker behind all the Darkstalkers' rebellion.

Yeaaapp i will probably play the game now