Blinkin89: I honestly don't see the problem.
Before the expansion was released it was already known it would add a side quest to the game which would be an adventure on it's own.
I loved playing this game and just starting a new game to (re)discover everything was just part of a great experience. :D
besides the fact it's not obvious at all, you actually can't get to the dlc from the end of the game, despite what the dev say. It shows the mission but you can't take it, and if you try to abort the mission you're doing, the game starts over the last mission of the game. So you can can only get it either from beginning or mid-game.
there was proably ways to deal with it more elegantly (even a readme file popping up would have been alright).
Apart from this minor inconvenience, a great addition to a great game. Challenging as it should, but never too hard (I spent quite sometimes reading the philosophers thing thinking there was a convoluted enigma, before realising I just missed a server and your teammate gives you the solution to the firewall).
Love the little meta game around the middle (and damn this weird windows command line that doesn't understand ls and rm)