Well, good time to stop for the night. Damn my need for sleep, and at least a bit of doing something other than programming. So, I got a bit done. There is a random assortment of trees and bushes. The models themselves aren't procedural but their placement is so it tries to create "forests" and it will be unique for every new game. I stole a few free tree and plant models online (well, made some with ngPlant and stole some) so they don't really look "in place" with the world, but I'm happy so far. There is a slight memory bug, it doesn't unload the trees very well so if you run fast enough, you can overload your memory (just save, quit, and come back in).
(To save: ` s RET)
There is also death in the game, but the only thing that will kill you are falls. So, create a character with a very low Athletics and Acrobatics and run around, you'll die or run out of fatigue. To recover fatigue, just hit SPACE, then select "R" for rest and enter the number of hours. You can also do that to see the sun rise and fall (or hit + or - for the debugging version).
There are some sound effects in the game, mainly for feedback. Also, if you are running around, you'll occasionally notice a message of "Your Athletics has improved!". If you hit F1 to go into your character sheet, you'll see it progress. If you make Athletics and Acrobatics your major skills (during character creation), and improve them 10 points, you'll notice a (+1) on your character's level. When sleeping is implemented, you'll be able to level up and increase your attributes.
Oh yeah, and the archive is under 4 MB and the uncompressed is under 12 MB. Procedural generation for the win. :D And the world is huge, takes about 15-20 minutes to run across it (with no tree placement). You can cheat by doing "` p 12000 6000 400 RET ESC" but be careful, you can fall to death. Maximum theoretical size is 16384 squares (32.7 km) across by 256 squares high, but effectively its only about 14k (28 km) square from one end of the country to the other.
New Alpha (0.0.2): http://mfgames.com/games/lethes-yarn/lethes-yarn-0.0.2.rar