If Emily is Away <3 generated the same gross revenue on the Epic Games Store, Kyle Seeley would keep approximately $1,636,120 - that's $430,116 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $86,744. 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 $1,206,005.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.