If Café Stella and the Reaper's Butterflies generated the same gross revenue on the Epic Games Store, YUZUSOFT would keep approximately $4,215,461 - that's $957,708 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $438,472. 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 $3,257,753.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.