If Hyperdimension Neptunia Re;Birth1 generated the same gross revenue on the Epic Games Store, IDEA FACTORY Co., Ltd., COMPILE HEART Co., Ltd., FELISTELLA Co., Ltd. would keep approximately $4,334,011 - that's $981,957 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $454,638. 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 $3,352,055.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.