@va!n: thanks mate! I really appreciate your comments. Here's the story about the vsync menu... if the vsync is on, then it's using the VBL to sync the display of the visual elements. Of course this works as long as the vsync is set on "application controlled" or similar in your graphics driver. There is no API (at least not general API) to force the VBL to on or off. You can only suggest it. That's a shame, but that's how it is...
In the menu I added an "experimental" detector for the vsync state. If your vsync is disabled then a warning message should be displayed. This detector measures the time between refreshes and if it's over the expected refresh rate (as given by Windows), then your vsync option may be set on "OFF". There is a "tolerance" to the measures as even if you have the vsync "ON", the time between refreshes is still not stable (it really sucks and shows again how much the PCs are inferior to the small Amiga

). Does it show such a message on your machine? I only have Nvidias so any ATI experience would help me improve the detector.. Anyway, if your vsync is forced on "OFF" and you leave the vsync option in the menu on "ON" then the intro disregards the warning. I made this on purpose as I do not know how much my detector would work.
So I would appreciate if you can check this with your graphics driver and let me know how the menu/intro reacts to your settings.
Best,
Stormbringer