If Steel Division: Normandy 44 generated the same gross revenue on the Epic Games Store, Eugen Systems would keep approximately $3,178,025 - that's $745,505 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $297,003. 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 $2,432,520.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.