TBH a game that describes itself in the name literally as a VN maker (not sure what E stands for) it does sure try to make the process of animating slightly too complex and limits some quite obvious aspects.
In blender I can quickly modify a models base mesh, create a shape key for inflation, or setup some kind of soft body physics sim or combine both or use an empty with deformation modifier and keyframe a stomach bulge/inflation animation, it's all kind logical, here, I can't even find an option to keyframe an inflation, they really went out of their way to make the system kinda weird, stuff like inflation/bulges should be fully automated in a "game" like this, why would I have to do it all myself in external more powerful animation software, might as well import the models into Blender and animate them over there, hell, I can get a mocap suit, or grab already made animations, change the rig, render with path tracing, do a proper cum liquid sim, can't do this shit in this.
What have they been doing all this time developing this...