If you mean those text files you find by shooting random stuff in the levels, than yes.

Remember how those files influenced your ranking in UC and often prevented you from getting an S because you just didn't know where they are? They changed that in DC, now the ranking is just about points, time, kill count and head shots.

That's good.  Finding the files should not have affected your ranking, but they were fun to find.

Are the head shots similar to UC?  Many people complained that it was too random or difficult  *rolls eyes*.  It made the game more challenging being that you had to actually aim.

Hey, getting headshots was hard! You had to shoot the slow-moving zombies in the head and everything...

They narrowed it down even more.  You had to hit them in the forehead. 

It was well worth it watching those brains explode all over the place though.  It was very similar to how Pachter looks when he tries to explain all of his false predictions.  

UC isn't a long game. It has 22 levels that average between 10-15 minutes of playtime, so it's about six hours long. In other words it's just as long as DC.

Now if you are talking about completing the game on all difficulty settings, getting all S rankings and unlock everything else, then UC clocks in at something like 30 hours. DC easily beats that with around 40 hours and if you add in that scores for the two player mode are saved seperately, you are looking at at least another 20 hours to get those S rankings too.