The game can now be played, although there are no enemies or goals.
I implemented a sprite system and input handling. The background automatically scrolls, and bullets can be fired and are moved and removed automatically.
The biggest problems I’ve experienced has been how sprite indexes are used. I assumed that sprite 2 was 1, but sprite 2 is actually 4. Some of the behaviors look like compiler issues; which was also an issue when I was developing Frog Feast. I just don’t completely trust a 65816 C compiler.