If House Flipper generated the same gross revenue on the Epic Games Store, Empyrean would keep approximately $50,166,810 - that's $7,669,710 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $6,704,565. 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 $39,809,962.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.