I recently downloaded the Half-Life 2 Gameplay Video via The extended combat sequences with guns and various vehicles, and the way both your friends and your enemies act in them, impressed the hell out of me; I felt like I was watching a movie. But the narrator for the video makes the point that this realism comes at a price: vastly complicated beta-testing.

This ties in with my own experience writing the FPS’s lowly, humble cousin, the text adventure a.k.a. “interactive fiction” game. Even in an IF game, where the player can’t shoot at whatever square meter he wants to, but instead is relegated to a relatively small selection of verbs and nouns, there are far too many possible combinations of actions to try them all yourself. Even for a small game, you need beta-testers – as many as you can find.

This need exists with any development, but for some projects, it can be ameliorated by Test-Driven Development practices. You think up the relatively small number of outcomes you want, and you make sure that you always get them.

With games, the challenge isn’t consistently trying out the small number of desired outcomes, but testing – and even thinking of – the vast number of cases that derive from those outcomes, and making sure they all work, too. And “work” is tricky, for IF games. You can’t just test for the right numerical output. You’re trying to make sure the text not only make sense, but is well-written, consistent, and is pitched just right for the times it’s going to appear.

This is why you need not one group of beta-testers, but two and even three groups. The first group tests out your initial game, the stuff you came up with with no outside help. Those really cool ideas that drove you to start writing it in the first place. These beta-testers will give you the first dose of sanity, and point you in fruitful new directions.

But at some point, these testers will have become too familiar with your ideas. They won’t be able to react like your real players will: confused at the confusing places, intrigued at the mysterious places, surprised at the surprising places. You need a second group to get fresh impressions of how well your ideas are working. You can’t mechanize that.

And ideally, once they’re done making sure your game is going well, you need one last group to judge the final result and catch any remaining erroneous details. Many games have that one last prominent bug because nobody saw the final changes with fresh eyes.

How about a fourth, a fifth, a sixth, a hundredth group? Nah. Beta-tester after beta-tester, your game will still have bugs. Beta-testing is the antidote to perfectionism.