Hello,
I was trying to build a DOS VM in Virtualbox to play games on (in my case using DR DOS 6.0). The DOS VM has a lot more functionality for other things I want to do and games are just part of it.

However, playing DOS games on a Virtualbox DOS VM has proven problematic. Case in point is SimCity Classic where the mouse jumps all over the place if you hold down the shift key and try to run a straight piece of road or whatever. It never recovers from going haywire. It never seems to happen until you hold down the shift key for that function, but maybe I didn't wait long enough.

DOSBox, however is the perfect solution for playing DOS games (especially once I learned to configure it), because it does a lot more to give DOS games what they need to run perfectly (i.e. mouse, video and sound).

I wonder if there is some way to create an "add-on" for regular MS- (or other) DOS as used on a Virtualbox VM to make games behave as flawlessly as they do in DOSBox.
Not DOSBox made to run inside of the DOS VM per-se, but rather something installed into an ordinary MS-DOS OS in the Virtualbox VM so that it is friendlier and so that you're still running the game 'natively' on the MS- (or other) DOS VM rather than just a DOSBox installed inside of it.

If you need clarification on what I mean, here it is: The entire purpose of the add-on would be to make the MS- (or other) DOS VM behave better with games (or any DOS app not having a text-based DOS interface).

I envision this working merely as something that 'tweaks' the currently installed DOS VM to provide it the correct mouse, video and sound settings needed to enable the host OS to work with it through Virtualbox.

Virtualbox (from what I can tell) doesn't really provide much in the way of DOS support...mostly later OSes.

It would be a great thing to develop and I think it would get a lot of usage since more capability can be realized from a full-blown DOS OS which is tweaked using the method you have.