1) The music in the castle plays from the beginning every time you enter it.
2) All buttons are pressed with a delay of 0.3 - 0.5 seconds.
3) All creature animations in battle are slightly jerky; there clearly aren't enough frames for the animations.
And on top of that, I noticed that although the graphics have become sharper, in reality, there's some kind of blur, i.e., everything is both sharp and blurry at the same time. I even thought that something might be wrong with my eyes or my monitor. But no, I launched the original with the HD Mod - everything is OK there. Apparently, Ubisoft implemented FullHD support very poorly, as a result of which objects don't fall into the pixel grid, and it all just looks awful.
P.S. Thanks for the tip about SoD_SP; I'll go check it out...