John Goering is the developer and publisher of Silent Shark on Steam. The store page describes him as an indie developer from Berlin and the creator of the head-tracking app SmoothTrack and the thought-organising app Mindscope. He posts on Hacker News as epaga; both of his Show HN posts about the game link its Steam page and silentshark.app.
A map-based WWII submarine sim set in the Pacific: plot contacts, estimate range with a stadimeter and build firing solutions by hand. The developer says Codex wrote all of the code.