Can't use pre-order freebie on Puzzle Agent
 

I got a coupon code for a free episode when I pre-ordered the New Sam and Max series. I tried using it for Puzzle Agent (seeing as how I'd already purchased everything else I wanted from Telltale) and it didn't work. Is this intentional or not, and if so will my coupon code work with Back to the Future or Jurassic Park?

It won't work on Puzzle Agent:

I doubt they would work with any of the upcoming series, either, as I think they're limited to games that have already been released.

Yeah, doesn't work with Puzzle Agent unfortunately.

Hey, would you mind giving it to me? Pretty please with cream and sprinkles on top?

Or me? :O

What does it work with? Is there any way someone from Telltale can confirm that the code only works on previously purchased games?

It was mentioned on the Telltale website in (sort of) a disclaimer at the time of The Devil's Playhouse's pre-order (the "disclaimer" listed the games that the coupon could be used on and only games older than The Devil's Playhouse were included).
I'm positive that it has also been mentioned on the forum by Telltale employees several times in the past but I'm not sure where.
There's this comment by Bonnie which is actually related to a Telltale Tuesday coupon, but applies to any Telltale coupon.
As far as I know, the coupon works with: Telltale Texas Hold'Em, either Bone game and any episode of Strong Bad's Cool Game for Attractive People, Wallace & Gromit, Tales of Monkey Island or seasons one and two of Sam & Max.

1. the coupons are for single episodes with a price of 8,95. Puzzle agent costs more money.
2. These coupons are usually only useable on games that were released before the time you got it.