Kinda neat, right? Well, thanks to the dudes at the GAF forums, I can share with you this little opportunity to test-drive, from the website of Echochrome author Jun Fujiki, the core level editor. This version isn't as polished as the final game, obviously, but the basic experience is here, and it's solid if you wanna give it a whirl.
If you get an error and it says you're missing a dll, get it here.
Who loves ya, baby?
[UPDATE: Durr, link is fixed.]
[Via NeoGAF]