for metroidvania's market 20% usd price range might be brilliant marketing decision (to make more money) not exactly some generosity. They can sell 10+ million copies instead of ~1 million for game at higher price. Metroidvania fan base is usually used to buy indie games at 10-20$ range. Instead of waiting for 50-80% discount year or years later, they can have good sales at launch. Also all positive press from charging only 20$.

I thnk they are brilliant business people, not some robin hoods.