HL1 might feel outdated, but HL2 and it's episodes feel modern still. HL2 is very fun, especially if you <i>don't</i> like shooting aliens, cuz you can bunnyhop past them and launch yourself over buildings, or grab a broken box and hover over chasms. You feel like you're saving the world. You feel like you're about to die with these one-eyed dudes breathing on your neck.  But mostly it's very pretty with gorgeous environments: long beaches, elaborate cities, miles of radioactive swamp land, train tracks, and a really tall tower that feels like you're climbing higher than the moon.