ScytheRexx, remember that Blizzard has no problem altering their own lore. How much has the WarCraft lore been altered across games (and I'm not even counting what they've done in/for WoW) ? Assume this is what has occurred here with the discrepancies between the SC1 manual story for the creation of the Zerg, and the in-game lore for them.
Overall, I liked it, but a bit too short, and I didn't like that it was more linear than WoL. In WoL you could jump back and forth between storylines/planets until right near the end, but in HotS, once you were on a planet, you were THERE and must finish before having a choice of planets again. It definitely gave it a different feel than WoL, but I liked the system in WoL better, as you can get tired of any one storyline IMO and want to do something else. Here you don't have that option. All of them were executed well, no doubt, but I prefer the flexibility. Personal preference maybe.
Also a little gripe here, I wish that they showed you the mission achievements on the screen where you "launch" the mission. I completed more than one mission and at the end seeing what I missed, going, "I could have done that! EASILY!" but unless you want to dive through the achievements window and record stuff down, it's not as easy as it could be, like the post-mission display is.