I read the title of this article and the first game that popped in my head was God of War 2. id take out the intro to frontlines .I mean the intro to MOH:frontlines is cool and all but when do you get to fight an enemy as big as a freakin skyscraper in the first level?
"were on as secret mission to get coffee and doughnuts but one problem, the germans drank all the coffee and ate all the doughnuts so now we have to go kick their asses"
You definitely should have put CoD4 in there. The first mission might not be so creative, but consider it an intro, or an 'in-game' trailer for the experience coming up. The real beginning is the live, interactive execution of YOURSELF!
If that isn't amazing and memorable, what is?
The first two chapters of Half-Life really shocked me in terms of immersion. Looking at piles of scientist's corpses, everything destroyed, malfunctioning lasers ripping the entrails of bodies around, guards struggling to survive with their 9mm pistols, and having seen the places completely okay before, it just gave me the thought "hey it was way more than a flashy explosion, now I messed up big time!". Epic feeling.