Final answer:
The different design would be a matched pairs design, where each participant is exposed to both conditions of the experiment. This allows for a direct comparison of the effects of music on gameplay.
Step-by-step explanation:
If the researcher chose a different design and had 30 players complete the game both with and without music playing, this would be an example of the matched pairs design.
In matched pairs design, each participant is exposed to both conditions of the experiment. This design is used when the researcher wants to compare two treatments or conditions on the same group of subjects while controlling for individual differences.
In this case, the researcher is comparing playing the game with and without music, and the same group of 30 players is completing the game under both conditions. This allows for a direct comparison of the effects of music on gameplay.