If Cyberdimension Neptunia: 4 Goddesses Online generated the same gross revenue on the Epic Games Store, IDEA FACTORY, COMPILE HEART, TAMSOFT would keep approximately $3,627,210 - that's $837,384 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $358,256. Epic charges 0% on the first $1 million in annual per-app revenue and then 12% on the remaining amount. On GOG (30% cut), the developer would earn approximately $2,789,826.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.