If you haven't played the first Zombie Cow adventure, Ben There, Dan That you should click away mid-sentence and nab it. Not only is it free, but there are plenty of adorable references to it in TGP that you won't want to miss. You'll once again control Ben and Dan (the digital alter egos of creators Ben Ward and Dan Marshall) as they travel through time to stop the invention of coathangers to try to prevent their past selves from summoning pseudo-aliens who brought about the end of mankind with a Magnum P.I. overdose.
And no, I'm not going to explain that any further. Seriously, you just need to play the games. By the end, TGP's like a pyramid of Russian nesting dolls, with jokes stacked haphazardly on top and inside of one another.
A lot of those gags are found through experimentation, with every combination of inventory item and background object generating a unique, clever response from our heroes. The work that must have been involved in creating that mountain of dialog is staggering to consider, especially considering the relatively skimpy $5 price tag.
If there's going to be a sticking point for some people, it's the graphics. Though I enjoy the sort of willfully amateurish art (which has taken a big step up since BTDT) I can accept it's not for everybody. Of course, neither are puzzles involving Hitler's bloody fecal matter, so the potential audience for TGP may be smaller than I have been able to admit to myself.
My earlier reference to LucasArts isn't an accidental one. TGP is, in a very real way, a love letter to fans of adventure staples like Monkey Island and Maniac Mansion. But rather than recycle the gags of their heroes, Ben Ward and Dan Marshall have been inspired by their spirit, and have come away with something equally rich, endearing and hilarious.