Hmm suddenly I am confused as to why scrolling messes with the greyscale o.O Using screenshifts doesnt move the checkered pattern, it moves the buffers, so shouldn't the greyscale keep working?  Or are you doing something dastardly for your tilemapping which makes this not work?

Good luck on the buildings.  I just saw your screenshot, and...YOU ROCK

Sounds great.
Sir, would you like this to have its own sub-forum?

Well, when it moves, even though it doesn't change the checkered pattern, the LCD delay is still there, so it mucks with other pixels.

Ah, so the lower speed when scrolling is whats causing the problems?

Hmm, this is kinda hard to explain from a phone.  I'll give a detailed explanation of why this happens next time I'm online.

I don't mind at all if you'd like to make your own version.  I'd be happy to help if you have any problems.

There are a couple of glitches, but the greyscale looks just fine on my calculator. One glitch is that if your y velocity is too high you can smash through the ground and glitch through walls.

So, I just finished designing a better HUD, and I'm quite happy with the result.  However, it required a tradeoff.  I decided that, because you do not need a lot of screen space to enjoy Motherload, I reduced the amount of screen dedicated to the map, and added more to the HUD.  The HUD is now quite a bit bigger, and takes up half of the screen.  On the other hand, I think it looks spectacular, and I'll be keeping it this way for now.
In other news, adding a full-byte map to the surface for buildings and such progresses, and I fixed the propeller code.
I still have yet to improve the digging mechanic, and it is still evident when digging down while scrolling, and left as well.