Portal 2

History

(November 2007 - February 2008) Directed Design Experiments

Directed Design Experiments

(March 2008 - August 2008) F-STOP

F-STOP

• Period where F-STOP was actively being worked on as Portal 2

Story

• Portal prequel

Characters

• Cave Johnson

(January 2009 - January 2009) Experimental Era

The Experimental Era follows Valve's failed attempt to transform F-STOP into a sequel to Portal and marks a complete restart of Portal 2's development. This era is named for the variety of gameplay experiments and new features that came about during this stage of development.

Some of the features that were added to Portal 2 during this era, such as light bridges and excursion funnels, were leftovers from Portal's late development.

• Portals return
• GLaDOS returns

Gameplay

• John Guthrie's idea: Glass football that exploded when it hit the ground

(January 2009 - Late 2009) Core Hub Era

The Core Hub Era demonstrates Valve's first attempt to create a proper follow-up to Portal after the cancellation of F-STOP. This era is named for its inclusion of a hub world that interconnected the game's testing courses. Initially, the player could complete the testing courses in any order, but the hub was later reworked to require that the courses be completed in a specific order.

A screenshot of the Core Hub and the Morgan Freeman Sphere.

Story

The player reactivates GLaDOS and attempts to repair her by retrieving six personality cores. The ending of this iteration of Portal 2 is unknown.

Characters

• GLaDOS (Carcass)
• Mel (early Core Hub Era) / Chell (late Core Hub Era)
• Aquarium Sphere
• Paranoid Sphere (early) / Morgan Freeman Sphere (late)
• Pendleton (?)
• Quint Sphere

(Late 2009 - May 2010) Multi-Core Era

The start of the Multi-Core Era is marked by the reworks that downplayed the personality cores and made the game more linear. Portal 2 was also announced during this era in March 2010.

Story

Chell is awakened from a simulation of a hotel room by Wheatley.

Wheatley is killed off by GLaDOS after her reactivation. Portal 2 did not have a proper ending during this era.

Characters

• GLaDOS
• Wheatley
• Aquarium Sphere
• Morgan Freeman Sphere
• Pendleton

(May 2010 - February 2011) E3 Era

The E3 Era is characterized by Portal 2's reveal at E3 2010.

• Co-op started development in May 2010
• Valve decides that Portal 2's story still needs work in October 2010

Story

Characters

• GLaDOS
• Wheatley
• Chell
• Aquarium Sphere

(Feburary 2011 - April 2011) Retail Era

Retail Era

• Finalization and release

Unused Content

Characters

Aquarium Sphere

The Aquarium Sphere was a personality core that was extremely fixated on aquariums. It was based on a commercial for the Oregon Coast Aquarium, which became an inside joke among Valve's employees. It was replaced by the Space Core.

A map from the singleplayer campaign in retail Portal 2 suggests that the Aquarium Sphere was in the game until a very late point of development. The map sp_a4_jump_polarity contains an unused logic_relay that is meant to play a sequence that involves a brief appearance of the Aquarium Sphere. Decompiling and editing the map to trigger the logic_relay does not fully restore the sequence because some of the relevant entities have been deleted.

Paranoid Sphere

The Paranoid Sphere was a personality core that was, as its name suggests, very paranoid. Its location during the Core Hub Era was on a pedestal inside a room that was protected by several turrets. When stood on its pedestal, the Paranoid Sphere would be boastful and brag about defeating intruders who attempted to enter its room. However, when taken off its pedestal by the player, the Paranoid Sphere would become very annoyed and threaten to "go mental".