[Dolemite]

The Portal games are funny, intelligent, and just plain fun. If you even have a passing interest in videogames, they're an absolute must-play.

Plus, they're old enough that they'll run amazingly well on a toaster, but they still look great even by today's standards, thanks in part to the overall design and how very effective the Source engine was at the time. Almost any Source-based game has aged well.

The comparison to Half-Life doesn't really work other than they're both first-person games and take place in the same shared universe, storyline-wise. Half-Life has some puzzle elements but is way more about combat, whereas Portal is a straight-up puzzle/strategy game.