Methods and systems for verifying and/or modifying game data for a location-based game, such as a parallel reality game, are provided. Game data for the location-based game can be verified and/or modified by establishing one or more mini-games to be played within the location-based game. Players can be encouraged to play the mini-game by providing a reward, such as a virtual reward that can be used in the location-based game or by providing another suitable reward. Mini-game data received from a plurality of players of the mini-game can be aggregated and used to update game data for the location-based game. In this manner, game elements, game objectives, and/or game play for all players in the location-based game (even players that do not play in the mini-game) can be adjusted based on the aggregated responses to the mini-game.