How to extract sprites from 'Yurikago no Sora'?

[physic]

Yurikago no sora (Japanese title : ゆりかごのそら) - Nonlinear

I'd like to extract sprites from the game mentioned above. Does anyone know how to do it?

This game is made by DXLibrary.

I found a tool called DXExtract, but I couldn't use it because I don't know the Decrypt key.