Zach Gage's Typeshift [Free] is a very clever take on word games, and I've quite enjoyed playing it. If you haven't played the game, you should first check out our review of it before reading the rest of this article. In a recent blog post, Gage talked about the game's design process and how he went about adjusting the game's difficulty curve. While the mechanic of sliding letters back and forth on a digital combination lock remained the same throughout the design process, everything else was designed and iterated upon repeatedly. He wanted a puzzle game where as you worked your way through it, the puzzle got easier to solve, which is apparently a common feature in crossword puzzles. However, in early iterations of the game the puzzles didn't seem to get any easier no matter how many words a player had solved.

To fix this issue, he used a three-pronged approach. The first was giving players contextual hints, the second was designing puzzles that could teach players how to solve other more difficult puzzles, and the final idea was what's called "clue puzzle" in-game, a type of crossword-like mode. The whole post is very interesting, especially if you're either designing a game or are interested in game design, so check it out here.