done with fight scenes recorded from the open source fighting game engine M.U.G.E.N
Stories outside of fighting are usually done in visual novel format, though there are some who just have a fight scene recorded, and story posted in descriptions. Random anime scenes and sound effects are sometimes added. Very rarely are there original animation and artwork. They are usually pasted together by using a photo editing program to edit pictures and a video editing program to throw together scenes. They are often posted as stand alone oneshot OVAs, or a series of a continuing story. They also tend to be animesque
because of how characters are based of Japanese fighting games. Fans of them tend to like anime.
Stories tend to be pretty generic, since they are based off fighting games. The usual tale is a martial arts story, and multi-dimensional crossover
Videos are typically posted on various video sharing sites. YouTube
is the most popular for it. Nicovideo also have quite a few in Japanese.