A few flaws have been fixed with the mod. I no longer have the ugly wooden planks "supporting" the level. The giant fizzler in level 2 is now correctly scaled. The portalgun appears correctly in the fourth level.
The problem with the 3rd level being awful is going to be fixed.
Anyway, I have a problem with the title screen for my mod. I have a New Game button, with a Continue button underneath it. The New Game button works as expected, but the Continue button doesn't do anything. Its command is set to "load autosave" and I have created and passed through an autosave trigger. When I type "load autosave" in the console, it loads the autosave, as expected. Does anyone know where I'm going wrong?