Narbacular Drop

Narbacular Drop is a freeware game for Windows released in 2004 by the then independent Digipen Studios. The game revolved around the adventures of a Princess dubbed "no knees", for her inability to jump, navigating through a medieval castle rife with dangerous obstacles. To aid her, she can use her magical abilities to conjure two types of portal gates, which if walked through, will lead to the other.

The majority of the staff of Digipen Studios later was consequently hired by Valve Software to produce the video game Portal.