Cloned Cube is a Portal mod. It takes place after GLaDOS' fall in Portal. You assume the role of Chell's secret clone. You have to escape or else you may just be tested to death. There is one obstacle. CUBiS is trying to kill you.
Gosh I just love the Source Engine! You go to admit that lightmapping can have some very cool effects.
Edited in an image editor.
indeed!
Wow. <3