The TI-83 is TI's most popular calculator, no questions asked. It has been adopted by hundreds of schools across the country as an updgrade to the TI-82, and it will not soon be replaced by another calculator. ASM documentation exists. If you'd looked for it, you would have found it. As I said, I know there are assembly documents out there, but every one I have read is missing something.
Game programming isnt just a matter of putting pixels on the screen and processing keys pressed.
I linked to the BEST ASM tutorial that currently exists. I can program in asm. I apologize for not even looking at the tutorial before replying. Its is by far the best tutorial I have seen for any calculator. By being stupid enough to buy it, you deserve a total lack of games.