The version included with DOTT doesnt look as good as the other one mentioned on the thread above, so I presume its the original version.
(If you want to run the version included in dott look in the maniac folder inside the dott folder and rename "maniac.ovl" to "maniac.exe" and then run maniac.exe to play.)
As far as the original version goes (the one with dott) it does run slowly (jerky scrolling etc) but as far as I can tell the original was this slow too so its running fine. I think this version only has pc speaker mode, there isnt any sound mode that I can see (so vdmsound wont have any effect). In short it runs fine as it was intended.
As for the newer vga version, that doesnt appear to have any sound besides internal speaker either, and runs ok too.
With all versions shift and a key changes options. Eg shift and m switches mouse on or off.
In conclusion then, as far as I can tell MM works perfectly in XP. But having not played the original on an old machine I cant be sure...