Dlsite:
https://www.dlsite.com/maniax/work/=/product_id/RJ249418.html
Story:
You're some sort of shota alchemist, a mother and her child (Or possibly protag's younger and older sister) accidentally ate some alchemical creation you made that make them grow really big. Generally, it seems like...
Roodt/Skunks, a RPG Maker veteran known for his sticky, fart, and giantess fetishes, has returned for his latest work, Attack on Giantess~World Defence Force~.
Always a fan of characterized bosses since his work in RPG Maker 2000 and coming off of his work on Magical Girl Riiru and Skunk...