You need to change the for loop conditions to A < 320 and B < 240. With that said, here are some tips:
(1) You probably want to examine the first post in the Routines sticky for useful routines. I recommend skeleton.zip if you don't have it already. It has an extended os.h and utils.h with more functions and keycodes. It's also smaller, which makes for cleaner uploads.
(2) C style dictates that your variables should be in lowercase, with constants in uppercase.
(3) while(!isKeyPressed(KEY_NSPIRE_ESC)); works (note no braces!)
(4) For sake of readability (at least in my opinion), it is a good idea to make your hex numbers have leading zeroes (so use 0x0F instead of 0xF).
Congratulations on having written your first Nspire program! Welcome to the wonderful world of Nspire programming

Well, with Ndless we can write our own boot loader to load a third-party OS, so that is possible.
RunOS exists, and can boot any Nspire OS version on a calculator running Ndless. Unfortunately, it is being delayed due to currently unknown issues.

w00t! The legendary games are on the Nspire now! Hopefully this will get a feature when it is released.

Yay! Big graphics
What are the new sprite dimensions?

apcalc: I posted a bmp to C converter in your Block Dude thread, since I didn't see this thread.
I think it is exactly what you wanted (it generated all of Ncaster's textures).
I would dread converting 576 pixels worth of data into an array too

Actually, if I converted Ncaster to integer arithmetic and optimized it, a combined floorcaster + ray caster should get about 15 FPS.

It all depends if the cosmic rays manage to mutate the blue lobsters.

What will they mutate into?

Blarg, right. Fixed.
Today's typo was brought to you by the letter "N"

I know, I wasn't saying it was hard

* DJ Omnimaga sighs

I wasn't saying that you were saying it was hard What I meant was that the framerate will naturally decrease as more features are added.