While there are some programs and games dedicated to polishing typing ability, only a handful of them can be described as both entertaining and good. Typing practice is not exactly associated with excitement; which is probably why the topic is mostly avoided.

However, Epistory creators managed to combine the core idea of typing with beauty and fun.

Everything in this game revolves around words, texts and typing. The menu can be navigated by typing commands, the abilities are switched by typing their names. The enemies are fended off with the power of typing as well. Every time the narrator reads out another bit of the enigmatic story, the text appears on the ground, where it stays at least until the end of the chapter. Also, the land is formed out of what looks like sheets of paper filled with writing. Every time the player unlocks a new patch of land, the world unfolds beautifully, like a cross between pop-up books and origami figurines. While the graphic style might seem simplistic, it goes very well with the aesthetic of a world of paper.

As for how typing works in battles, I personally find it very well implemented. One might complain that the set up looks hardly exciting - the main character typically stands in a stone circle during longer battles and the enemies approach her - but this is not the case. Once one of the beasts comes too close, the girl and her companion fox are killed and the entire fight sequence has to be repeated. Additionally, enemy types are varied not only in terms of size and speed but also the number of words assigned to them (think of them as their "health") and their difficulty.
The player collects four elemental abilities throughout the game, each one having a different debilitating effect on adversaries (fire burns additional word, ice freezes enemies in place, lightning jumps between them and wind gusts push them back), but once the player learns new skills... monsters immune to all skills but one corresponding to their colour start to appear. This makes the combat a bit nerve-wracking at times - the enemies approach slowly but steadily, getting closer and closer while the player tries to make no mistakes.
Personally I think that my experience with Epistory helped me improve the way I type. Although, I have never loathed and feared my mother tongue more than I did when I saw monsters adorned with words like "gżegżółka" and "pięćdziesięciogroszówka". Playing Epistory in Polish is not for the faint of heart.

Apart from fighting enemies and unearthing lost treasures, the player has to face some environmental puzzles as well. Sadly, this is probably the least satisfying element of the game. The puzzles are on the easy side to the point they can be considered a bit boring. There really isn't much to talk about - some ice physics, pressing switches here and there, finding a code and pressing some more switches in the right order.

TL;DR Epistory is a great experience, with beautiful visuals and a cool idea. Also, playing it can actually improve your typing skill. Beware the Polish language in this game.