So I just finished the game :-)
Spoilering the rest of the post for obvious reasons.
The post credits "surprise" (as the achievement calls it) was epic! The mention of the Morpheus project made me go to YouTube and watch the Morpheus conversation from the first game again.
Overall, DX:HR is a very well made game. It has its flaws and it may not achieve the epicness of the first one, but it's probably the best attempt we could have hoped for. As I said earlier in the thread, expectations of large conspiracies and plot twists cheapen them when they finally happen and make them predictable. That said, although the game had an overall Deus Ex feeling to it, it didn't feel like stuff was happening on a scale as big as the events in the original. Maybe it couldn't. Perhaps this was the only way to fit a prequel story that wasn't bigger than the JC Denton story, which it logically couldn't be. On the other hand, perhaps I'm making up excuses because I really liked and enjoyed the game, or because I just finished it and the first game's music is stuck in my head from listening to it after the credits (how epic was that?).
I admit to total fanboyism!
Question for everyone, whether you played it, finished it or nothinged it:
Do you believe that this will achieve the long-term status of the first one? Will we be talking about how good it was in 10 years and hold it up as a milestone in game history? Will we be telling then 15-year-olds that they should go and play DX:HR and try to get over the dated graphics because the story is really really good?
That is all!
Late edit: Steam has my game time clocked at 41 hours, but I'm sure it can be completed in half the duration if you don't try to explore every corner. Still, helluva lot longer than probably every single shooter made in the last 5 years.