Can you try switching the graphics to low quality? A lagging cursor is usually caused by anti-aliasing (which is turned on with the high quality graphics).
and while i'm on the topic of resolutions, why is there no widescreen support? is everyone at telltale running the game on a 17" CRT at 1024x768??
This has been discussed in other places on the forum but the gist of it is that widescreen resolutions use a different aspect ratio than our games do. Supporting both would actually take a lot more work than people usually think, so for the time being, widescreen is not supported.