TOKYO—In some ways, Hisako Akitani’s videogame store was just another small family business that closed when its owners got older and tired of fighting the internet.

Yet when Ms. Akitani stood behind her shop counter for the last time on a recent Sunday, some of the top names in Japanese videogames, including companies like Sony Corp. , came to pay tribute to a woman whose frankness made her one of the industry’s most powerful and unlikely influencers.

Ms. Akitani made her name with unvarnished views about games and how they are marketed, taking stands that larger store owners or game publications often wouldn’t because they were afraid of spoiling relationships.

“She’ll talk to you about anything with complete honesty,” said Ryozo Tsujimoto, managing corporate officer of Japanese videogame company Capcom Co. and a creator of its hit franchise “Monster Hunter.”

At her shop, called Ma-Ya, and since the early 2000s on a blog, Ms. Akitani would dress down game makers for missing promised launch dates. She recalled the time she scolded a company that advertised famous voice actors in its game but gave them only one-word grunts for lines.