And it works, and it's pretty damn easy to use.
It'll be hard to make something that'll stand out from the crowd though, it's all very very prefabbed.

But on the other hand, I haven't got a single good idea for a puzzle, so I don't think I'll actually be making any.

Cube icon is very appropriate. 

The Portal fan in me thinks this is a fabulous idea as it'll hopefully provide hours more gameplay.

The snob in me wants to run around telling people it's not proper level design and they should get to grips with Hammer if they want to be real level designers.

I'm so conflicted. I think I'll run with the first opinion so that nobody thinks I'm a horrible horrible person. 

You can take your generated levels into Hammer and really personalise them. 

DaZ

I think that will be the real appeal. Design the puzzle in an awesomely streamlined environment and then take it into Hammer if you want to do a bunch of custom visuals to surround it. The easy linking of stuff looked great! 

Maybe it saves .map files which can then be opened with hammer?
Easy prototyping! :D 

Well that's good to know Daz. Hopefully it'll inspire a new generation of source mappers! 

and it's already given me plenty of ideas for TrenchBroom. 

ctrl+drag to clone items. 

Go go microtransactions!

The compiling seems pretyt slow though, there should be a 'preview' without lightmaps.