This game is not related to the story of the Half-Life 2. Something goes mad because the human race failed in the experiment, and it connects with another world. The resident in the another world is crazy due to the mistake. We should restore the situation. As for this game, almost all are made only from the basic function of HL2. Having fiddled with the code for the chapter unlock is the only exception. You will learn the degree of freedom of the expression of HL2 is very high. K.S.(Koumei satou)
It has such a rich atmosphere, it's not a master-piece, but it feels like it.