You may think this free Steam game is not worth it, but trust me, it is.
User Rating: 9 | Half-Life 2: Lost Coast PC
By free steam game, I mean there is still a valid, free, legal way to get this game. But you might also think "This will waste my time". Well, you are right and wrong. It is a good waste of time. It is short and it is a sort of showcase of Source's capibilities with the commentary of renowned game programmer, Gabe Newell and other members who built the Source Engine. This takes place in Saint Olga in the Half Life universe, you end up at the shelling facility, where zombie-making headcrabs are put into missles, and shot into towns to enforce the Combine's rule. Combine are the evil people in the altered-stormtrooper-looking uniforms. This as I said showcases the Source Engine, like the physics, lighting, AI, interaction, water effects, and all the other stuff the Source Engine can do. I recommend this to anyone who wants a free, fun to play, worth playing AND replaying game. 
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