...or programming for them, anyway. Just to see if I could do it, I tried to put in a black and white version in GoSub2, and it worked. To play a B&W version of GoSub2, set the color switch to B&W (from color.) Also, I've added an easy version if you switch the left difficulty to A (yes, I know that's backwards, but I consider left difficulty B to be normal.) Easy mode is marked with the letter E at the beginning of the score. Gosub2 in Black and white means someone could do this for the original Game Boy. What I did to get the switches to work is something like this:

if switchbw then c=1

if !switchbw then c=0

and then, have COLUPF, COLUBK, and COLUP1 be different values, like for instance, COLUPF=u.

Then set u to either a color or a shade of gray depending on whether c=1 or 0.

This is exactly what I did for the easy/normal mode, except I had s be the value of wither the left difficulty switch be A or B. The only problem is that you can't change the screen to black & white in the middle of a game (but who would do that, anyway?)

And by the way, my computer seems to be working normally now.