If Our End of the World generated the same gross revenue on the Epic Games Store, 橘子班, 大好网 would keep approximately $1,398,895 - that's $381,592 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $54,395. 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 $1,017,303.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.