Puzzle Agent is part of Telltale's "Pilot Program", so any sequel would rely on having sold well
Right now's a GREAT time to be getting into Telltale games, everything in their store is 50% off(excluding Poker Night at the Inventory and Back to the Future). My personal suggestion? A 1-2 punch of Sam and Max
, Seasons 1 and 2. Season One can start off a bit rough around the edges, but overall it's great, and Season Two is amazing. I prefer it over Tales of Monkey Island
, but that series can come off a bit more polished in terms of production values.
Another thing you could try is to buy an episode of each series and try them out on rapid-fire. Both of the first two Sam and Max seasons, Tales of Monkey Island, Wallace and Gromit, and the Strong Bad season all have "Season Upgrade" options, so you can try one episode and see if you want to grab the rest!
I also wouldn't suggest playing anything out of order. Some people may say it's fine, but I've found it to be best to play from start to finish in any given season.
Another thing to note is that Telltale has an upcoming season based on the Back to the Future franchise. That's another thing you could order, and get the month-to-month episode release experience.
Note that in most of Telltale's other games, the puzzles are less "contained" and "overt". Generally speaking, a Telltale game is similar to the old point and click adventure games, in that the puzzles are more ingrained in the story. The specific style of puzzle gameplay in "Puzzle Agent" was something of a departure and an experiment for Telltale, one that I think they pulled off extremely well, but the distinction should be made.
In terms of games to avoid, I'd say you should steer clear(at least for now) of Telltale Texas Hold-'Em, Poker Night at the Inventory, and Bone. The first two are Poker games and aren't really indicative of Telltale puzzle game style(and Telltale Texas Hold 'Em was more of an engine prototype), and Bone is somewhat atypical in its design as it was Telltale's earliest adventure property. Interesting, not bad, but not the best introduction to Telltale, I don't think.