Iteration is super important when testing out a game. From what I've seen, it's the key to making the gameplay and game features better. Here’s how it works:

1. Getting Feedback: During playtests, you receive feedback from players right away. Watching them play your game gives you important clues. Players might notice problems that you didn’t see.

2. Spotting Problems: It’s not just about what you see. Players might also share their frustrations or confusion. This helps you figure out what needs to be improved. For example, if a lot of players have trouble with the same level, that's a clue that you need to revise that part.

3. Quick Changes: You can make changes fast based on what players say. If you notice that the fighting system feels awkward, you can fix it by changing the animations or how the hits are registered, and then you can test it right away.

4. Improvement Cycle: Iteration keeps the process of making improvements going. Each time you get feedback, you make changes, then you test it again. You keep repeating this process until the game feels just right.

In short, iteration helps turn a rough idea into a great game. Without it, you might end up with something that players don’t enjoy at all!