I found the solution! Though not an excellent one
![Sad :(](./images/smilies/sad.gif)
The way is:
1. Run the game with VDMSound;
2. When speed'n'sound glitching starts, switch to desktop via ALT-Tab;
3. Call Task Manager (CTRL-ALT-Del) and change the NTVDM process priority to somewhat in the area of average, above or below average. Wait for some time.
4. Switch back to game - it is as it should be!!!
And the only problem is
5. Repeat as necessary
![Sad :(](./images/smilies/sad.gif)
It can be quite annoying to repeat the procedure for many times, especially if you get killed often.
The longer you wait, the better the results (about a minute in desktop gives enough time of proper work to pass a level).
Any suggestions to improve my methodics?