Well, after about 9 hours of work (plus 3 hours for breaks), my 4k game is mostly done. I've got fall damage, crushing damage, chat, troll control, some graphics, bug-hunting, minor gameplay tweaks, and 67(!) bytes to go.
There is still some compression I can do; I've already saved a huge amount of space by stuffing data into the map file (useful loophole, that). Once I compress all my remaining procs down into one-liners (and half-liners and sixteenth-liners) and #define the hell out of it, I should have a little more space to play with.
The gameplay needs some work right now; the beginning of the game in particular is quite slow. Changing the starting positions on the map would probably help... but that's an issue for another day.
And now it's time to say goodnight. Goodnight!