This level was originally included in Half Life 2, but was eventually distributed separately as a free demo. There were several reasons for this, and the desire to show off the beauty of the engine was perhaps not the most important one. The level itself consists not so much of shooting as of admiring the world around you. First there is very realistic looking water in the harbor, there is also an introduction to the fisherman and character drawing. Then there is the pleasure of the settlement and the monastery on the cliff.
In general, now it is difficult to imagine how this level would “fit” into the already tight schedule HL2. Therefore, all he can do is stand apart, which is even better.