If you aren't familiar with Lingo 1, Lingo 2 can be played on its own. If you're thinking about getting only 1 or 2, I would recommend 2 first since it's more accessible and overall higher quality. I would best describe the Lingo series as Antichamber with word games. The puzzle design is distinctly "The Witness" in how it tackles rule teaching and breaking.

Lingo 2 is a difficult language puzzle game in the "rule discovery" subgenre, my personal favourite. It also throws in a non-Euclidean map and an unsettling aesthetic. As with the best rule discovery games, once rules are discovered, they are used unexpectedly, turned around, or combined with others. The game makes you question everything you think you know about it and rewards you for thinking out of the box. I would recommend this game to players that love language puzzles, are native English speakers, and aren't put off by note taking. Lots of it. You should also be someone that enjoys confusing maps and doesn't mind backtracking through areas repeatedly. The main mechanic of the game is collecting letter keys, which unlock new puzzles/areas just like the regular kind of keys. Very clever.

If you ever find yourself annoyed at how many possibilities there are in a seemingly open-ended puzzle (3 letter word that rhymes with "eye" anyone?) just keep in mind that the game loves hiding additional hints in the environment or the answers of surrounding puzzles. The context is often as important as the hint. The puzzles are well thought-out and the tricky ones make you feel soo smart for solving them.

Except for the hatchling puzzle in The Unyielding. ♥♥♥♥ that puzzle.

For players of its predecessor, this is an excellent sequel that improves upon the original in every way. If you liked Lingo, you'll love Lingo 2.
The original had incredible puzzles as well, but accessing them was impeded by artificially difficult navigation. A common gripe of Lingo 1 was finding puzzles and being unable to find them again once you figured out the solution. Lingo 2 keeps the same twisty impossible geometry but adds a way to teleport to previously unlocked areas. This mechanic keeps the same sense of discovery without punishing you for not being able to execute the same pick-a-path again. However, this game does involve significantly more backtracking with the new key collection mechanic. Lingo 2 is also a much more polished game- the graphics, puzzle design, navigation, and additional mechanics are all several steps above the original. You can really tell that the Lingo series is a passion project of the solo dev, Brenton Wildes, and I can only hope that one day we may be blessed with a Lingo 3.

This game is not for everyone, but for those who it is, I can't recommend it enough.

Really fun and clever word game, and with custom levels. even more fun in store.