Portal was the gem hidden inside Valve's Orange Box. Its simple yet charming story combined with its advanced physics helped it become one of the most loved games of this generation. You play as Chell, a human guinea pig in Aperture Labs, who has to use a portal gun to teleport through a variety of deadly rooms.
All types of gamers fell in love with Portal's intelligent gameplay and charismatic yet devious robot GlAdDoS, who lead players through each test chamber and potentially certain death. Portal's out-there mechanics
delighted players and sparked a new type of creativity in game design.
Top 100 Video Games of All Time #13 - Portal