Featured favorite:
Observation
Play as S.A.M., the AI controlling a research station that has mysteriously been transported to Saturn s orbit. You ll help Dr. Emma Fisher discover what happened to the rest of her crew by solving puzzles, searching for clues by bouncing around to different cameras, uncovering lost data, and controlling probes to go where Emma can t.$25 at GOG
Testing:
Portal 2
Staff pick
Play solo or team up with a friend to break the laws of physics at the behest of GLaDOS, a murderous computer who wants to test out your skills with portal-making technology. There are two separate campaigns, with co-op mode requiring you to closely work together to make your way through Aperture Science Labs. You can even use the game s editing tools to design challenges that your friends can play through.$10 at Steam