Well good luck to anyone trying to crack sam and max episode 4. (Which I bought) I was curious so I, shall we say, had a poke around. The game is protected by 'SoftwarePassport - a greatly enhanced version of the Armadillo Software Protection'.
Basically it goes something like this. You open the original, it unpacks the real exe into memory and runs it as a separate thread, then shares memory across the thread (I think) using some fruity variety of API calls. You can’t get an unpacker for the armadillo packer, I didn’t bother trying any generic ones.
Anyway once you have the application running it generates a fingerprint of your hardware and sends it off to the activation server at drh.digitalriver.com with your account information. If the registration is successful the server will reply with a valid serial key and also tell you how many registrations you have left, you start with 10. I believe that means you can install your copy of the game on 10 separate computers, or 10 times on the same computer after 10 sets of hardware changes.
If the key is valid then something magical happens. I haven’t managed to work this part out. I’m not sure if the game writes into the registry, or into a file, or into itself or maybe even into some hidden file in some hidden folder deep in the recesses of the windows directory structure. But once its written there’s no getting rid of it.
And then you can launch and play the game. Which I enjoyed, very much

, and was glad that it was a good deal harder than the first three.
Anyway I was curious to know why no cracks had appeared for the new game, and now I do, because it has *really* good anti-crack protection. The unfortunate part of having really good anti-crack protection is that crackers only crack for the challenge of cracking. So naturally they look for the most challenging and naturally they will hit armadillo’s system eventually.
For the meantime at least it looks as though the telltale engineers have found a sufficiently good means of protecting their games. Which means future piracy will be nil.
A cautionary note however: Remove the phone activation. This is a major weak spot. I’m no professional cracker, I only play around for fun and education, but a professional cracker could probably extract the generation algorithm which turns a fingerprint into a serial key for comparison using a low level debugger like softice. Once the algorithm is known they could simply write a generator which generates keys given fingerprints. (I know you think no one would bother for such a cheap game, but I’m betting you want to use this system on more expensive games in the future.)