GTA IV Achievement help please

Ok, this is probably really obvious but on GTA IV there is an achievement called Liberty City Minute where you have to complete the story missions in less than 30 hours.

When it says story missions does it just mean the story missions indicated by a letter on the map? Or does it also mean taking people on dates, such as Packie's Sister and doing all the random character's missions? Also if left with an option to let someone live or die, does either descion affect the story as in relation to getting this achievement?

Thanks to those that can help.

Yeah just do the missions with the letters. You don't have to do the dates or anything.

I think the story counted as 60% towards completion, so you're over half way there if that's the case, but I'm not too sure I haven't played it in aaages.HeyFonz