I'm not aware of the issue you mention, the mouse sensitivity is normal for me and I haven't had anyone else report it being lower. The "compulsory delays" are also most likely a technical glitch that shouldn't occur for most players. Do other AGS games work normally for you?
Edit: on second thought, there are three short paragraphs at the very beginning of the game which are part of the intro and are unskippable (each of them appears for roughly 4 - 5 seconds). Maybe you meant those? They will be skippable in the full version.