Given the lag that the regular Gameboy ROM's experience, I think a GBC game would not only require huge grayscale to get even ok looking graphics, but also would lag even more than it does already! 

Just for the record, My calculator is a S - 0406F  and it works great

Mmmm, ok.  I'm not an assembly guy, so I wasn't sure.

Well just for clarification, Modulus is a type of division that gives you the remainder, not the answer.  It is useful because if I have an increasing value 1 2 3 4 5 6 7 8 9... and I take a Modulus # of it, the result will be a looping value up to that number.

For instance, A % 4, (% is the Modulus operation) where A is increasing by 1 each iteration would yield:
0 1 2 3 0 1 2 3 0 1 2 3

So if I took the Modulus of the X coordinate, I could use it to yield a positively increasing loop while moving to the right (0,1,2,3,0,1,2,3...) and a negatively increasing loop while moving to the left (3,2,1,0,3,2,1,0...) and when standing still the sprite would not change at all.  The benefit to this method is that you don't have to do any monitoring of the keys, as everything is entirely dependent on only the x coordinate. (Monitoring the keys can be difficult when using xLibs real(8 ) because of the multiple key commands )

Hmmm, This is all very interesting...

Unfortunately I can not contribute as of now, because I can't find my calculator!
I think i left it in a safe place though, so i should be able to pick it up tomorrow.

EDIZT:  Ninja'ed by Tsukasa   Congrats on your first Ninja .  Anyway, I don't know if we are sure the TIOS doesn't use them, some peoplpe theorize that all of it is critical for USB Linking.

The part bout GEH's was interesting.  I'm surprised you didn't weave them into your history

Alright, I finished implementing save files, so now the Menu is able to do more than just look cool I also finished the pause menu, which is the most advanced I've ever written.   It has 2 pages, one for viewing keys and one for viewing items.  On the page where you view Items you can select the current Item that you want to set to [Alpha].  On both pages it gives you the options to save your progress, restart the room, or exit the game.

 I made the pause Menu ASCII because I find that when people pause, they don't want to wait for their pause menu to load!   And because it is also simpler than switching the graph screen out.

The Saving is going to be a lot like Trapped (See? I told you I was inspired! ) and Zelda in that when you save, it only saves your progress when you entered the room, so that any mistakes you've made that prevent you from exiting the room don't become a problem, and just to decrease the save file (Though its not very big).  Restart room is an option also created for this purpose, just in case you get stuck or the like.  Restart room will NOT restore your health to previous health though! I had a lot of people take advantage of that in Trapped to the point where everybody was finishing the game with all possible lives.