While the method of solving problems is unique, the actual plot structure is very standard. You still have the transfer to a school, the tsundere childhood friend, the noble girl, the beast girl, etc. It doesn't reinvent the wheel regarding the cast archetypes.
(which is an adaptation of the eroge), then a "guide" might mean: eroge de subete wa kaiketsu dekiru top
Instead of killing the Demon King, Kaito realizes Lilith is a "hidden route" heroine. By choosing the "I understand your loneliness" dialogue option, he turns the final boss into a loyal wife. She single-handedly solves the monster invasion crisis. While the method of solving problems is unique,