Here's some footage of Portal's gameplay for anyone who hasn't heard of it:
In the Portal series, the player controls an anonymous female protagonist armed with the Portal gun. Although it sounds, and looks, like a first-person shooter game, the portal gun is a unique item. It allows you to shoot beams of light that create portals connecting one spot to another via teleportation. This simple premise is masterfully played with, as in order to progress through the levels you must use the portals creatively to manipulate gravity and physics to allow your character to reach otherwise inaccessible areas. Although you must contend with various dangers such as sentry guns or high energy beams, there is never an emphasis on fighting, instead on outsmarting the various traps. It was highly celebrated by the gaming community for both its innovative gameplay and its compelling storyline.
A game like Portal, and its new sequel which has been called "one of the greatest games of recent years" by the Guardian, shows that hardcore gamers do not always demand intense violence. With clever enough gameplay, game designers can appeal not just to mainstream gamers like the Sim games do, but instead to hardcore demographics and become a beloved touchstone of the community.