If Road Redemption generated the same gross revenue on the Epic Games Store, Redemption Road, Pixel Dash Studios would keep approximately $5,958,860 - that's $1,314,312 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $676,208. 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 $4,644,548.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.