EDIT: The thing that is sad it that they did not included their newer wrapper so there is no aspect ratio correction to 4:3, game is stretched with wrong aspect in full screen mode (unless you fiddle around with your graphic card control panel options...). They could simply include their newer wrapper that has option to enable aspect correction, this older version was probably included out of simple laziness.
There is no aspect ratio correction because it is outputting at fixed resolutions; 320x240 is a 4:3 resolution. It is the graphics drivers' fault for not defaulting to GPU scaling with Maintain Aspect Ratio as the default for digital cables, instead just outputting a raw image that is obviously going stretched by the monitor, which usually stretch by default also.
Really, you should have your GPU set to do the scaling and correct the aspect ration anyway; it is much less performance demanding than when the application tries to do it. Why this isn't the default is beyond me.