Gameplay in Portal 2

Portal 2 continues to challenge players to use portals to traverse rooms in unusual manners, such as flinging, in which the player uses the magnitude of the momentum gained by gravitational acceleration through the blue portal to cross a wide gap out of the orange portal.

Portal 2 is a puzzle game presented from the first-person perspective. Normally, the player, as either Chell in the single-player campaign or as one of two robots, Atlas or P-body, in the co-operative campaign, can move, look, and carry and drop objects, as well as interacting with switches. The goal is to maneuver the characters through a number of test chambers in the Aperture Science facility, traversing the chamber from the start to the exit. Though the player-character can take some damage for a brief period of time, they will die under sustained injury and be restarted at a recent checkpoint; however, characters are equipped with "long fall boots" that absorb the shock of landing after a large vertical drop. The player must figure out how to overcome seemingly-bottomless gaps, evade pools of toxic liquid, or avoid line-of-sight or even disable robotic turrets to safely arrive at the exit.

Initial levels provide a tutorial on general movement controls and interactions with the environment. After these levels, the player will be required to solve puzzles in test chambers within the Aperture Science Enrichment Center using the "portal gun" (the Aperture Science Handheld Portal Device), a device that can create two portals connecting two surfaces across space. Players solve puzzles by using these portals to move unconventionally between rooms or to use the ability to fling objects or themselves across a distance. The functionality of the gun has not changed between the games, but within Portal 2, players can take advantage of the transmission of other physical effects through the portals.One example is the direction of Excursion Funnel tractor beams or Hard Light Bridges through portals to provide surfaces or areas which the player can use to move the player-character or specific objects across obstacles. While early technology demonstrations included the use of Pneumatic Diversity Vents, a series of transport pneumatic tubes, and the interaction of their suction or venting power through portals, these do not appear in the final game, as the technology was not quite perfected by release.

The game also introduces special paint-like gels that can be used to impart certain physical effects to a surface such as Propulsion Gel that boosts Chell's speed as she crosses a surface, and Repulsion Gel that allows her to bounce from a surface. A third gel type, Conversion Gel, allows any surface coated with it to accept portals.The player will be required to determine how to transport that gel to appropriate surfaces using portals in order to progress.The gels can also be applied to objects, such as the Aperture Science crates, that affect their own physical nature. 

Water can be redirected to wash away gels applied by the player, returning the surface or object to its normal state. In addition to the returning but cosmetically redesigned Storage Cube, there are new types of objects that assist the player, including Redirection Cubes with prismatic lenses used to redirect Thermal Discouragement laser beams, Aerial Faith Plates that can launch objects placed on them, and spherical Edgeless Safety Cube, which made a brief appearance in the original game in one of the advanced chambers.The heart-decorated Weighted Companion Cube, used by GLaDOS in the first game to make Chell form an emotional bond to the inanimate object before incinerating it, also appears briefly in the sequel.

While most of the single-player game takes place in the test chambers created by GLaDOS or her personality cores, there are times where the player will need to move behind-the-scenes in areas beyond the test chambers as they are reconfigured, leaving the player free of GLaDOS's observation and control.

The game includes a two-player co-operative mode in addition to the single player mode. This mode can be played by two players at the same computer/console via split-screen, or through two remote players at their own computer/consoles; Microsoft Windows, MacOS X, and PlayStation 3 users can play with each other regardless of platform. Both players control separate portal guns and can use the other player's portals as necessary;each player's portals are of a different color scheme (blue/purple, and orange/red) to help distinguish between the two sets. Because of the number of possible portal combinations, the test chambers that the players proceed through are much more difficult than the single-player campaign, requiring the two players to work together. Initial chambers set each robot in their own separate section of the chamber, and their solutions teach the use of the communication tools and portal use to complete. Later chambers are less structured, and require the players to use both sets of portals for laser or funnel redirection, launches, or other maneuvers to reach the exit. Should either robot die, a new robot will be recreated shortly after, allowing players to continue on the puzzle without restarting.The game includes voice communication between players for this mode as well as split-screen for players playing locally. 

Online players have the ability to temporarily enter a split-screen view to help coordinate actions. Players have the ability to "ping" walls or objects on the game's levels as a means of informing the other player what they need to do, starting countdown timers for concerted actions, and perform "gestures" with their partner, such as waving or hugging.Borrowing on the concept from Left 4 Dead, players, both in the co-op and single player campaign, can see the outlines of placed portals through walls and other obstacles to identify their locations. The game tracks what chamber each player has completed, and allow a player to replay chambers they have completed with other partners who may have not yet completed that chamber.

Valve has stated that both the single player and the co-operative campaigns are about each 2 to 2.5 times as long as the original campaign in Portal, with the overall game five times longer than the original.Erik Wolpaw estimates each campaign is about six hours long.

As with previous Valve games, Portal 2 contains in-game commentary from the game developers, writers, and artists.The commentary, accessed after completing the game once, appears on node icons scattered through the game's levels, either where the development team found significant changes from their original ideas, or where ideas failed to work out for the game.

Gameplay in Portal

A representation of how the magnitude of linear momentum is conserved through portals. By jumping into the blue portal, the character is launched out of the orange portal and onto the platform on the right.

A more advanced portal technique. The character builds up speed using two blue portals, to reach an otherwise unreachable area. The second blue portal is carefully created mid-air, after exiting the orange portal for the first time, destroying the first blue portal in the process.

 

 

In Portal, the player controls the protagonist, Chell, from a first-person perspective as she is challenged to navigate through a series of rooms using the Aperture Science Handheld Portal Device (portal gun or ASHPD). The portal gun can create two distinct portal ends, orange and blue. The portals create a visual and physical connection between two different locations in three-dimensional space. Neither end is specifically an entrance or exit; all objects that travel through one portal will exit through the other. An important aspect of the game's physics is momentum redirection. As moving objects pass through portals, they come through the exit portal at the same direction as the exit portal is facing and with the same velocity with which they passed through the entrance portal. For example, a common maneuver is to jump down to a portal on the floor and emerge through a wall, flying over a gap or another obstacle. This allows the player to launch objects or Chell herself over great distances, both vertically and horizontally, referred to as 'flinging' by Valve. As GLaDOS puts it, "In layman's terms: speedy thing goes in, speedy thing comes out". If portal ends are not on parallel planes, the character passing through is reoriented to be upright with respect to gravity after leaving a portal end.

Chell and all other objects in the game that can fit into the portal ends will pass through the portal. However, a portal shot cannot pass through an open portal; it will simply fail or create a new portal in an offset position. If a portal of the same color as an existing one is created, the previous portal is destroyed. Moving objects, glass, special wall surfaces, liquids, or areas that are too small will not accommodate portals. Chell is sometimes provided with cubes that she can pick up and use to climb on or to hold down large buttons that open doors or activate mechanisms. Particle fields known as emancipation grilles exist at the end of all and within some test chambers that, when passed through, close any open portals and disintegrate any object carried through. The fields also block attempts to fire portals through them.

Although Chell is equipped with mechanized heel springs to prevent damage from falling,she can be killed by various other hazards in the test chambers, such as turret guns, bouncing balls of energy, and toxic liquid. She can also be killed by objects falling through portals, and by a series of crushers that appear in certain levels. Unlike most action games, there is no visible amount of health; Chell dies if she is dealt a certain amount of damage in a short time period, but returns to full health fairly quickly. Some obstacles, such as the energy balls and crushing pistons, will deal this necessary amount of damage with a single blow, thus causing instant death.

The portal gun allows several possible approaches to completing the various test chambers. In its initial preview of Portal, GameSpot noted that many solutions exist for completing each puzzle, and that the gameplay "gets even crazier, and the diagrams shown in the trailer showed some incredibly crazy things that you can attempt." Two additional modes are unlocked upon the completion of the game that challenge the player to work out alternative methods of solving each test chamber. Challenge maps are unlocked near the halfway point and Advanced Chambers are unlocked when the game is completed.In Challenge mode, levels are revisited with the added goal of completing the test chamber either with as little time, with the least number of portals, or with the fewest footsteps possible. In Advanced mode, certain levels are made more complex with the addition of more obstacles and hazards.

The PC, Xbox 360 and Mac OS X versions of the game also feature a number of Achievements the player can earn by completing tasks. Achievements range from normal gameplay requirements, such as obtaining the Aperture Science Handheld Portal Device, to various tricks, such as using portals to jump a particular distance. As with other Source engine games since Half-Life 2, Portal can be played with commentary enabled; special icons will appear in the game that the player can activate to hear how certain parts of the game were developed.

Portal 2

portal 2

Portal 2 is a first-person puzzle-platform video game developed by Valve Corporation. It is the sequel to the 2007 video game Portal and was announced on March 5, 2010, following a week-long alternate reality game based on new patches to the original game. Though initially slated for release in the last quarter of 2010, the game was postponed to the week of April 18, 2011. The game was released by Valve through Steam for Microsoft Windows and Mac OS X, while the PlayStation 3, Xbox 360 and retail Windows/OS X versions of the game are distributed by Electronic Arts. The game's release on Steam was preceded by a second multi-week alternate reality game, the Potato Sack, involving 13 independently-developed titles, culminating in a distributed computing spoof to release Portal 2 several hours early.

Portal 2 primarily comprises a series of puzzles that must be solved by teleporting the player's character and simple objects using the "portal gun", a device that can create inter-spatial portals between two flat planes. The game's unique physics allow momentum to be retained through portals, requiring creative use of portals to maneuver through the test chambers. Other gameplay elements were added to Portal 2, including tractor beams, laser redirection, and special paint-like gels that impart special properties to objects they touch. Similar to how the student team of Narbacular Drop were brought into Valve to expand their game to the basis of Portal, the team from Independent Games Festival-winning DigiPen student project Tag: The Power of Paint was hired by Valve to incorporate their game's paint mechanic into these new gels.

Within the single player campaign, the player returns as the human Chell, having awakened from stasis after many years. Chell must navigate the dilapidated Aperture Science Enrichment Center and its test chambers with the portal gun while the facility is rebuilt by the reactivated GLaDOS, a rampant artificially intelligent computer. With a larger story, Valve introduced additional characters, including Wheatley, a robotic personality sphere voiced by Stephen Merchant, and recordings of Aperture Science CEO Cave Johnson, voiced by J.K. Simmons. Ellen McLain reprised the role of GLaDOS. Additional music from Jonathan Coulton and The National appear in the game. Portal 2 also includes a two-player co-operative mode in which the player-characters, the robots Atlas and P-body, must work together to complete each test chamber using their own individual portal guns.

Though many reviewers were concerned about the difficulty of expanding Portal into a full sequel, critics universally praised Portal 2. The game's writing, pacing, and comedy were highlighted as stand-out elements, with critics applauding the voice work of McLain, Merchant, and Simmons. Reviews also highlighted the new gameplay elements, the game's challenging but surmountable learning curve, and the addition of the co-operative mode.

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