> By the way, Roadblasters control works much better than in MAME. But there's a big > problem with these ports.... they take sooo little size on the screen.... the rest is > just a black border around it. And there's no way no increase it. > > This is how all games look
I guess they just picked the biggest screen size supported by your video driver in which things would fit.
stretching and aspect ratio correction are expensive (for older hardware) too if you want them to look good and don't have an exact resolution.