This has been bothering me for quite a while since some of my favorite video game/visual novel series have gotten animated but were unfortunately rushed for some reason. Corpse Party: Tortured Souls, for example, is an 4 episode OVA anime based off the first game of the series. It was okay, but it's no doubt that it was rushed. The Steins;Gate anime, on the other hand, was adapted so well into an anime that people weren't required to play the game in order to understand the story. 

Because the Asian anime industry is a cruel industry that doesn't care much for human rights. Executives can get animators on the chopping board if they're unable to animate within the requested deadlines, so because of this, animators have to cop out animation quality for necessitate reasons.