For Leo, that 640x360 resolution was the peak of technology. He spent hours on forums like Mobile9 or Dedomil , hunting for the perfect .jar file that wouldn't "letterbox" on his screen. Every megabyte was precious, every sprite-based explosion a masterpiece.

That is nearly a 90% reduction in fill rate. You can write a software renderer that updates every single pixel 60 times a second using BufferedImage and still have CPU cycles left for game logic and physics. It allows you to focus on gameplay, not optimization hell.