Secret Files 2 sadly does not live up to its predecessor. Story, characters and puzzles are all weak at best.
So let us start with the most important part of any adventure game: the story. No I won't go running around the planet saying that the story of the first game was great, but it was entertaining, (mostly) well thought through and did not suffer from any major weaknesses. Sadly, the same cannot be said for the second game. The story is poor at best: a fanatic sect is out to rule the world. Need I say more? We find our two protagonists from the first game now separated, but what do you know: they happen to stumble upon the same conspiracy at the same time! On different locations at first, but it hardly comes as a surprise that they will meet in the game. What makes this statistical impossibility even worse is that the main villain of the game even points out the fact that there is no way that this could happen by coincidence, which almost gets you rooting for the bad guy.
But that's not all, because apart from a weak story, the humor in the game is not funny at best. Since I know a bit of German and since the game is originally German, I could easily spot out a couple of lines, which might have been funny in German, but lose their meaning in English completely. Add to that the fact that the voice acting is rather poor (at some points more than other points) and you've got yourself sitting behind the game wanting to punch the protagonists in the face every so often.
One could also argue that the graphics are outdated. One would even make a good point with that. But since I'm not a big graphophile, this is one of the few things that didn't bother me too much about the game. What did bother me besides the stuff that I've already mentioned are the facts that the puzzles are way too easy and the game is very short. I went through it in a couple of hours. Had the puzzles been a bit more difficult, the game could have lasted two hours longer easily. But since most of the puzzles consist of using and combining the proper objects, and since you very often find about 90 percent of those objects on the same screen, you tend to go through those rather quickly. There are a few word puzzles and the likes in the game as well, but these too suffer from oversimplification. And what's even worse is that you can often combine items in your inventory even before combining these things make any sense. This leaves you walking around with constructions that will get you arrested at the airport without any clue as to why you would have to make such a construction. So in short: the puzzles are too easy and often don't make sense. And even with them not doing that, they are still way too easy.
I won't go as far as to say that I've wasted valuable hours of my life with this game, but I do know that I found it to be worth less than I've paid for it. A lot less. So unless you find this one in the bargain bin, I suggest you stay away from it.