"Welcome to UrfEarth!"

I finally got the game's scene background tiles to properly evict when unseen, and to scroll. In a 1024×768 window, the game is now playably fast in Opera (the FPS changed from ~4 to ~16), and Mozilla Firefox's FPS jumped from ~10 fps (after a gradual slowdown) to ~23 (with consistency). Now I just have to scroll sessile creatures with the scene (again) and deal with the small IE-now-runs-at-~40-FPS-in-that-same-window-size-instead-of-~60 and background-now-looks-slightly-waffley problems. The former, at least, stops once the background stops moving; the latter depends on client-area size and background position.