I have made it as far as the DMux4Way, but have encountered a problem. My implementation of the chip refuses to load for some reason. It won't load directly, or via the .tst script. The simulator offers no helpful comments - the screen just remains blank. Other chips I have completed load just fine.
Depending on your screen configuration, the status line at the bottom of the simulator window can be hidden. If you load something and it looks like nothing happened, it may help to move the window up. The best way to do this is using the keyboard since it lets you move the window farther (on Windows, at least).
Alt+space, M, up-arrows will let you move the window up and see the status bar. The window will jump back down if you hit enter or nudge the mouse.