SirPrimalform: Yeah, just had a look at TWD on GamersGate and sure enough it's a Steam key. I'm pretty sure it's standalone if you buy it from Telltale's site so I've no idea why it couldn't be DRM-free in this bundle.
Are you saying that you can buy DRM-free games from Telltale's site? That would be news to me, all I've ever bought from them directly had SecuRom or some similar DRM on it, and so far they haven't shown any interest in pleads from their direct customers to remove the DRM from games that have been available DRM-free elsewhere. Personally I'll never buy from their website again.
I was hoping this bundle would at least enable me to pay a few extra bucks for the DRM-free versions of all the games I already *bought* from Telltale, but sadly the ones I'm most interested in in this regard, that is the complete Sam & Max series and Strong Bad, are not included for the most part. Figures. Well, maybe I'll give a few bucks to charity for The Devil's Playhouse.
So, yeah, the reason why TWD is just a Steam key is probably that Telltale has a pretty ambivalent attitude towards DRM and DRM-free games. I guess we won't see any of their future games released on GOG from Day One, due to their fear of piracy (or whatever it is that makes them set such great store into their DRM - which has caused me quite a few issues in the past without Telltale Support being able to solve them).
EDIT: Nevermind, I didn't read all the post above mine before posting, sorry.