Balancing difficulty
Balancing the difficulty of a typing game is a challenge that deserves its own section to go over everything you have to consider to do it right. The first thing to understand is that, within the typing game audience, there is no correlation between game literacy and typing speed. There are casual gamers typing at 120 words per minute because they type at work, and there are hardcore gamers who spend most of their time playing all sorts of games but never learned to touch type. This means gameplay difficulty and typing difficulty have to be evaluated separately. If there is a difficulty setting (or adaptive difficulty, we’ll get back to that), it often makes sense to split game difficulty (for challenges not related to typing) and expected typing speed (to challenge typing speed or accuracy).
I believe the gap in typing speed is harder to bridge than the gap in game literacy or skills. Typing AGGRESSION to attack an enemy takes 6 seconds at 20 WPM but only 1.2 seconds at 100 WPM, which completely changes the pace of the game. Either we accept that the game is not accessible to everyone who can type, or it must adapt to its players.
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The first metric we can use to evaluate difficulty is the word length. Touch Type Tale’s algorithm generates words within the range specified by the designer. They usually choose between 4 and 6 letters, but there are specific cases where single letters or long words are used. The same goes in Epistory, where the word length depends on the enemy archetype.
In Nanotale, word length is less restricted because you receive mana for your spells when typing words (based on the square of the number of letters), so it compensates for the added challenge. Similarly, Typing Heart and Outshine give more points for longer words. In these cases, the word length is not used to manually set the difficulty in the level design, but the metric is still used to scale the reward with the challenge.
The second metric we can play with is the time given to type each word. In Epistory, the difficulty setting only changes the speed of the enemies moving towards you (and the time between spawns during battles, which has the same effect). In Typing Hearts, the goal is to reach a given score before a time limit. A higher difficulty increases the target score, giving you more words to type in the same amount of time.
Another possible metric is the complexity to type a word. As Diego Sacchetti says, “you must assign a difficulty to each word not only based on its length but also on the spatial relationship among all keys for that layout.” While it’s true that BANANAS is faster to type than APRICOT, I think this is going too far for most use cases considering that it’s harder to automate than simply counting the letters in a word.
A more practical (although a bit subjective) metric is the players’ familiarity with the word, or as Diego puts it, “how likely it is that a word has been already typed by the player in everyday typing.” An obscure or made-up word is harder to read, thus it takes more time to type correctly. “Words like HELLO have been typed so many times by everyone that the finger movement pattern is completely memorised, like a move from a fighting game. A never-before-typed word with the same characters like ‘Lohel’ becomes more difficult to type just because there’s no previous experience in typing it. [..] Since we integrate this word within the context of a meaningful sentence, finding the ‘best’ words to fit a difficulty curve can become a very hard task to do.”
If, as in Textorcist, you have full sentences, then the number of words to type in a row is also a metric. Even without time pressure, more words equals more opportunities to make mistakes, so longer sentences are more difficult. In the long run, typing too much leads to attention fatigue and even physical pain. Gameplay phases where speed is encouraged should be limited to short sessions. In Outshine, for instance, Hugo Bourbon split the levels into three short sections for this very purpose. “Each section is finished in about three minutes and concludes with a series of three sentences to type as fast as possible (to get more points).” In-between sections, there is a break that can last as long as needed to recover. “With longer sessions of about four minutes, fast typers start to feel pain in their fingers.”
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I wrote above that gameplay difficulty and typing difficulty should be considered separately. Accordingly, their difficulty curves do not have to match, and they do not both have to increase over the course of the game. A game like Touch Type Tale develops the strategy aspect throughout the game and assumes a stable base level of typing skill: “As soon as you have an average typing speed, almost all of the difficulty in our game comes from the strategy, but if you’re not good at typing, like if you are just starting to learn how to type and you have never used a keyboard before, then the difficulty will come from typing.” Malte Hoffman compared this to other strategy games where players measure their APM (actions per minute). In Touch Type Tale, improving your WPM (words per minute) does help in some ways, “but there is a form of diminishing returns” the higher you go. “There is a tipping point where it goes from being hard because of typing to being hard because of strategy.”
In contrast, a game like Outshine has a difficulty curve that comes solely from the typing challenge, once you’re familiar with the enemies behavior. “The huge gap in fire rate (typing speed) between players makes the balancing complicated” explains Hugo Bourbon. That’s why he offers five different difficulty levels (affecting speed and number of enemies) and optional “modifiers” for variety that fast typists use to increase the difficulty for themselves: resetting the word if you mistype, mirrored words, only the next three letters visible (forcing you to look at the screen), and even game over at the first mistype. “That’s the most extreme, I don’t know if it’s even possible.”
One note while we’re talking about challenging typing: players generally underestimate their typing skills because they’ve never had to use them under pressure. While it creates a marketing problem with players thinking the game is not for them, it is something we can take advantage of in our design. The average typist regularly glances at their keyboard but intuitively knows the key positions. If you push them to type faster, they tap into that muscle memory and do better than they expect (at the cost of more mistypes, though, so maybe don’t challenge accuracy during those frenetic typing phases). Even if challenging typing is not the core of the game, I believe a bit of stress highlights the key moments, as we did at the last wave of Epistory’s battle phases. You can always cheat to achieve the desired effect without any real risk of failure.
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With a wide range of typing skills, some designers naturally want their game to adapt to players. When designing Typing Hearts, Ettome thought to himself “I want an adaptive difficulty!” He made an onboarding phase where players type for narrative choices, from which he also gets speed and accuracy data. The first battle in Epistory acts as a tutorial and is very easy. If the player fails that battle, there is a special trigger that drastically reduces the difficulty. On Backspace Bouken, Benjamin Bushe and Jake White also use the first tutorial encounter to get your typing speed and set the game difficulty from a list of 3 presets. Setting the difficulty at the beginning is nice, but they told me they would have liked to keep it adaptive through the entire game.
In Epistory, the difficulty is a hidden value that is adjusted from the player’s successes and failures during the game. For example, winning a battle increases the value by 10, losing decreases it by 20, and being killed by a roaming enemy decreases it by 2 (I don’t recall the exact values, but this gives you an idea). What I didn’t like about this method is that gameplay and typing difficulty are mixed: losing a battle because you don’t adapt your strategy still makes the enemies slower. Losing two or three times in a row makes the difference noticeable and players, who are still typing at the same speed, feel cheated.
In Nanotale, we changed the evaluation method to a continuous evaluation of the player’s WPM. The time between each character input is counted, starting after the first letter of each word. The last 50 typing sessions are saved (typing several words in a row counts as one typing session) and averaged to get a WPM value that affects the speed of enemies.
This new system works well for Nanotale, where the gameplay revolves around puzzle solving and combat tactics. But adjusting the difficulty too precisely can become a problem if the game challenges typing fast at its core. Ettome had a prototype where the score objective was adjusted to match the number of points players should be able to get within the time limit. The difficulty was so close to what the player was capable of that there was no challenge. His playtesters always beat the levels just within the time limit, and the game experience was poor. Eventually, he developed another metric to replace the classic WPM, the “APPC”. It stands for average point per character, which is how many points a player is able to get out of one typed character on average (taking points multipliers into account).
In other words, he added the player’s ability to strategize to maximize the multiplier into the mix—the opposite of what I said I wanted after Epistory. The lesson here, I guess, is that as a designer, you want control over simple metrics, so you understand how your adaptive difficulty works and are able to tweak it. But for the players, the effects of the adaptive difficulty have to be “blurred” and smoothed out, so they don’t notice it (and feel like it’s the natural progression of the game).
Regardless of how (and if) you implement adaptive difficulty, it’s important to be transparent with players and give them options. In Nanotale, for example, you can enable the adaptive difficulty, in which case the WPM calculated by the game is displayed in the options menu. You can also disable it and select your own WPM value for the game. We don’t have “easy” or “hard” levels for typing speed, which would be arbitrary and judgemental. Instead we have “20 WPM”, “30 WPM”, and so on up to “120 WPM”. There are also a few accessibility options (like auto health regeneration) but those are separated from the typing level on purpose.
For Sophie Schiaratura, our PR and marketing manager, the adaptive difficulty is a feature that people like. Being able to say “don’t worry, the difficulty automatically adapts to everyone” is reassuring for those who believe they aren’t good at typing and for parents who want the game to teach their children.
There is a large diversity of game literacy
and typing skills in the population of players
Think of gameplay difficulty and typing speed as separate metrics.
Adaptive difficulty can make the game feel dull if implemented poorly, but it opens the game to a much larger audience if done well.
Leave players options to customize at least the typing side of their experience.
There are other design challenges that I left out to avoid making this part way too long. You can find more in the final “bonus” section, including how language and cultural differences influence the typing difficulty. But for now, let’s dig deeper into the typing gameplay.
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