If The Swapper generated the same gross revenue on the Epic Games Store, Olli Harjola, Otto Hantula, Tom Jubert, Carlo Castellano would keep approximately $2,685,096 - that's $644,679 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $229,786. 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 $2,040,417.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.