wpegg: I'm afraid that sometimes people on the forums simply don't have an answer. It's not that we're ignoring you, just that we don't know.
Have you logged a support request with GOG?
Can you also define what you mean by 'buggy'? I doubt I can help if you do, but it may remind someone else of something.
Some general things I'd suggest from experiencing mouse difficulties. If you're on a cordless mouse, try a corded one if available. If you're connecting via a hub, try connecting direct into one of your motherboards USB ports. Generally try to reduce the number of things in the way between the mouse and the PC.
Sorry I can't be more help.
If I move the mouse slowly, it usually won't move at all. I have to move the mouse really fast to get fluid movements, but even after that it's difficult to press buttons to play the game.
I've now opened a support ticket with GoG, let's see what happens.
I have no problems with my mouse elsewhere, although I did have the same problem in Star Wars: Dark Forces (another game you need to play in DosBox). I could look left and right when playing the game. But when I was in the menus the same problem occurred from Constructor.
I can connect my mouse to the motherboard directly. It's a Logitech G700, it's wireless but I can plug it in to be wired as well.