 Early in its development , the development team planned to exclude portals from Portal 2 . For five months , Valve focused on a gameplay mechanic called " F @-@ Stop " , the specifics of which as of January 2013 are unknown outside of Valve , because the developers considered using it for a new game . Though the new mechanics prompted some positive feedback , every playtester expressed disappointment at the omission of portals . Following a report in Kotaku of some leaked aspects of the game 's plot then under consideration , Newell directed the team to reconsider its plans for Portal 2 , including the lack of portals . 
