Agrhh, mapping errors are my worst enemy ever. I've been having problems making maps. I also have bad news for the level:testchmb_a_05.
The level has to be how it REALLY IS from portal. When I made it funny, the map didn't load for some reason. It said in the console: Uhh, well, I forgot. More bAd news for the level when you get the upgraded portalgun: I couldn't make it funny because I lagged SOOO!!! BAD Whenever I try editing it. So... That level is once more, the original Portal level. :(
Now, other stuff. I got some more prefabs but they didn't work out so well. They spawned somewhere where I didn't want them to be. So I removed them. :( Now, anyways, I'm supposed to make MY own stuff right? Ehh, well, I am using Valves perfabs, I hope I can do that here.
Nothing else to say now. Other than anything else, everything is GREAT! I'm going to get back to mapping now. :)