This is a great game but why does it say bad download or not enough storage even though my storage is not full yet

Love this game but I don't have enough space in my device

This game has many characters based on reality too…I like to play this game as it is a battle royale game and I like it.it's graphics are too good and we can adjust it by oiselves too. But, the problem is that it needs so much space as my ipad is only 16GB space so , I can’t play it please fix this problem ASAP. Thanks and Regards.