On Sunday evening, I worked through the NUSIZx and Missile demos and finally the playfield on Tuesday before moving on to Chapter 3: Movement.
I didn't have too much difficulty with the last demos in the graphics chapter and only had a few errors to correct each time before the program compiled correctly. In Chapter 3, however, I am having some issues. The ship sprite is not positioned correctly and, when it moves, it messes up the screen. I've compared my code to the original several times, but still haven't pinpointed the exact problem.
After having another look at the code, I discovered that, ONCE AGAIN, I had typed "LDA" where an "LDX" should have been! Here's what the fixed code looks like and where the problem was:
Edited by arwanderer