Narbacular Drop

Narbacular Drop is puzzle video game developed by Nuclear Monkey Software, and is the spiritual predecessor to Portal.

Synopsis
A princess, called No-Knees due to her inability to jump, was admired by her entire kingdom. A demon, imagining her kidnap would help in his quest to conquer the world, captures No-Knees. He then locks her inside a cage in his mountain lair, under patrol of his Impy minion. However, Wally, the spirit of the mountain, was mad at the Demon for creating his dungeon lair inside his home. He tells No-Knees he would assist her in escaping as long as she helped him to defeat the demon. To escape, Princess No-Knees is allowed to use Wally's magical power; she can look at any two flat surfaces and break reality, making an instant link between them using two portals. She'll then use this to travel through five different chambers all the way to the final boss.

Development
Narbacular Drop ' s main focus was to use the portal system, a technical mechanic that had emerged in a few games by that time, as the key feature in a game. With the addition of allowing the player, as well as other objects, to go through the portal, the game includes a wide range of gameplay possibilities.

The game development had 4 "milestones": Pre-Alpha, Alpha, Beta, and Final. Each version included mostly fixes and level coding.

The final version of the game includes the model, animations, and textures for the final boss, the Demon; however, the final battle was never properly implemented, and even though the final credits appear, the game never actually ends. Consequently, Wally does not show himself and Princess No-Knees never escapes the dungeon.

Jeep Barnett, a developer of the game and current employee at Valve, stated on the now-defunct forums of Narbacular Drop, that the final chapter of the game, Fire with Fire, "was a hint as to how to beat the final boss who would [throw] fire balls at you that you need to redirect through a portal."