If L.A. Noire generated the same gross revenue on the Epic Games Store, Team Bondi would keep approximately $9,893,356 - that's $2,063,791 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $1,212,730. 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 $7,774,260.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.