Narbacular Drop is a puzzle game developed by Nuclear Monkey Software. It was released in 2005, and was made by some students attending DigiPen.
When it comes to the gameplay, one can say that the gameplay reminds you of Portal (Nuclear Monkey Software worked on Portal as well). You can't jump in this game, so the only way to pass through obstacles, is by using the portals. If there is anything I can complain about when it comes to this game, it'd have to be the controls. It just feels slippery.