Balancing a game's difficulty can be tough. Different players will enter the game at different skill levels depending on whether they've played similar games or not. Their learning curves during the game will be varied as well, making it tricky to decide how difficult to make the game without making the game too difficult (frustrating), or too easy (boring).
Above is an approximate graph of balance zones based on the player's skill and the game's difficulty. As player skill increases, the difficulty must also increase to keep a balance. The balance zones are as follows:
While it requires testing, balance and player feedback to really balance a game, this article will cover four tips and tricks for designing game difficulty, which I've learned through my game development experiences.
1. Know your audience.
Knowing your audience is important in almost every aspect of game development, and is also important for game balance. Who do you expect to play your game? What games will they have played before yours (and how similar are those games to yours)? Knowing the answer to these two questions will help you guess what skill level the players will start with, and which balance zone they prefer. A casual game should assume that the average player has a low skill level, and doesn't want to be particularly challenged. A niche game should assume that the average player enjoys that niche and has played many similar games before, and so has a high skill level and enjoys a challenge. Having a good read on your target audience gives you a starting point to balance the game, and will make your initial balancing more accurate.
The takeaway point here is that the better you understand your audience, the more you can cater the game to that audience - and that applies to a lot more than just the balance of the game.
2. Underestimate the player's learning curve.
The player's skill will increase throughout the course of the game, and so the difficulty of the game has to increase to compensate. However, overestimating the player's learning curve is worse than underestimating it (and most developers tend to overestimate their players - not everyone is as good as you!). If you overestimate the player's learning curve, players who learn quickly may get a good balance, but the rest of the players will not be able to keep up with the curve and the game will continue to get harder and harder until they can't continue. Whereas if you underestimate the player's learning curve, players who learn quickly will still enjoy the game even if it's not as challenging for them (they will simply feel that they are awesome), while the rest of the players will still be able to keep up with the game difficulty.
You've probably played a game you liked a lot in the beginning, but then it became so difficult that by the end it was no longer fun to play. The final boss was impossibly frustrating, and you probably resorted to walkthroughs or outright gave up. This is a situation you want to avoid at all costs. A player is far less likely to quit because a game is too easy.
The takeaway point here is that it's easier to lose players by making a game too hard than by making a game too easy. So, when in doubt, underestimate the player's learning curve (actually, it's good practice in general to underestimate your players).
3. Don't reward skilled players by making the game easier!
There are a lot of games that reward their players for doing well by giving them more upgrades. But what this is basically doing is making the game easier for players who already found the game easy, while giving nothing to the players who are struggling. A lot of these games try to compensate for these upgrades by increasing the difficulty. While this may balance the game for skilled players, it makes the game even more difficult for the players who were struggling and didn't even get the upgrades. This is a very fast way to lose players. Really, you should "reward" players who do well by making the game more difficult, and "punish" the players who do poorly by making the game easier, in essence dynamically changing the difficulty to suit the player. While this seems like an oxy-moron, there are ways to make higher difficulty feel like a reward, and lower difficulty feel like a punishment. For example, I've seen games that, if you do well enough, reward you by giving you access to a second ending. The gameplay to get the second ending is a lot more difficult than the first ending, but the reward is that you get the second, perhaps better, ending.
You can also hide the fact that the reward is making the game more difficult. For example, you could give the player upgrades if they do well, but increase the difficulty even more than the benefit of the upgrades (and don't change the difficulty for those who didn't get the upgrade). While this seems like cheating the player, most games that give upgrades increase the difficulty to compensate - this is the same idea, simply limiting the increased difficulty to the players who got the upgrades.
The takeaway point here is that while it's important to give rewards to players, making the game easier to a player who is already doing well is not really a reward in the long run.
4. Allow players to change the game's difficulty.
It's impossible to balance a game perfectly for every potential player. So, giving the player a choice on how difficult they want the game can help widen the audience. Players who want casual fun can lower the difficulty, and players who want a challenging experience can raise the difficulty. If the player can adjust the difficulty in the middle of the game, then they can even compensate for their learning curve. Just be certain to never punish a player for lowering the difficulty. It is a choice they are making to improve their gameplay experience. They may already feel bad about having to lower the difficulty, you don't need to rub it in their face with a punishment. If you do anything, reward players who increase the difficulty.
The takeaway point here is that players (sometimes) know themselves best, so letting them choose the difficulty can help balance the game to suit their personal needs.
Testing and tweaking are still the most important methods of balancing a game. No matter how well you balance the game yourself, unless you are the sole audience of the game, you will need to know what it's like for others. Getting friends to play and comment on what they found easy and difficult is a great first step. A beta test that gets comments from the actual target audience of the game is even better. But these four tricks can improve the balance early on, and in doing so help focus the design of the game.
(Reposted from my personal blog: http://david.fancyfishgames.com/)