Portal

Portal is Valve's genre-defining first-person physics puzzle game, released in 2007. Chell wields a Portal Gun that creates paired teleporting portals on flat surfaces — you can portal an object across a chamber, redirect momentum, and confound gravity. The dark comic writing by Erik Wolpaw and Jonathan Coulton (and singing AI antagonist GLaDOS) made it a cultural phenomenon. Portal 2 (2011) added local- and online-co-op puzzles.