"Gameplay changes" refers to alterations or modifications made to the way a game is played, including its mechanics, rules, controls, or overall experience. Full definition
This upcoming pack will kick the difficulty up a notch, introducing a variety of gameplay changes which emphasize the survival aspect of the game, along with some new achievements and items. (thatvideogameblog.com)
Don't make major gameplay changes months after release. (andymerrill.com)
As far as gameplay changes go, there are two that I think improve the Persona 4 experience greatly. (zeboyd.com)