Hunting this on behalf of the developer — I handle promotion for him, I'm not the maker.
Hyperion Starfall is a fixed-screen arcade shooter for PC and Android, built solo. The unusual part isn't the game so much as the build: no advertising SDK, no analytics, no telemetry, no account requirement, no energy timers. On Android that's close to unheard of.
Monetisation is levels 1-8 free with a single one-off unlock. That's the entire model.
Happy to relay any questions to him.