KFC gave away free food and up to $50k with its mobile-based game - The Great Bucket

Hunt (https://www.lifehacker.com.au/2021/06/kfc-bucket-hunt-game/), and they would like to obtain a good understanding of the players' experience. KFCwould like to conduct some marketing research, adopting a qualitative research method, i.e., interview. However, they are unsure if it is the best approach to gather useful information in this case compared with quantitative or mixed research methods.

Question: Please critique the proposed qualitative research method (i.e., interview) for KFC (P/S: Please provide the critique based on the context of KFC rather than general)