If Chained Together generated the same gross revenue on the Epic Games Store, Anegar Games would keep approximately $6,208,807 - that's $1,365,438 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $710,292. 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 $4,843,369.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.