Game Definition (Portal 2)

"Games are voluntary attempts to overcome unnecessary obsticles."

-Bernard Suits (1978)

" A game is a rule based outcome, where different outcomes are assigned different values, The player exercise effort in order to influence the outcome, the player feels emotionally attached to the outcome , and consequences of the activity are negotiable"

Jesper Juul, Half-Real (2005)

Rule based system: A linear progression where you complete levels by reaching an exit using portals and realistic physics. You cannot place more than 2 portals or fall in water.

Different outcomes:  They are multiple outcomes to the levels though only one linear exit, So you either die, Or Progress.

Influencing the outcome: The player can influence the outcome by either completing puzzles or die trying, They do this through using the structure of the rooms, water, pits, boxes, lasers, buttons, goo, and turrets to complete said puzzles.

Emotional Attachment: The player feels emotional attached to the character as her backstory slowly gets revealed and how she is trying to escape. It is her goal to do so and is in the players hands whether she does or not. In addition to this the more effort you put in the more reason you have to finish as you want to complete what you have put so much time into.

Negotiable Outcomes:There are several ways to complete the game such as 'speed-running' or just enjoying the story therefore the outcomes of of the game are negotiable. You could also play co op in a variety of ways further changing outcomes